Study Design — Flashcards
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What is the ANOVA test used for? (biostatistics)
prevalence (epidemiology)
meta-analysis (epidemiology)
incidence (epidemiology)
What kind of study compares one group of people with disease to another group of people without disease and looks for an exposure or risk factor that explains the difference?
alternative hypothesis (H1)
Explain how a case-control study works.
Which direction does the tail go in a positive skew distribution? Negative skew?
In a normal distribution, what is the relationship between mean, median, and mode?
Name and explain three common measures of central tendency of a distribution (biostatistics).
Study Design US Medical PG Flashcards - Medical Study Cards
Master Study Design with OnCourse flashcards. These spaced repetition flashcards are designed for medical students preparing for NEET PG, USMLE Step 1, USMLE Step 2, MBBS exams, and other medical licensing examinations.
Study Design Flashcard Deck - 233 Cards
Flashcard 1: What is the ANOVA test used for? (biostatistics)
Answer: Compare means of three or more groups.
Flashcard 2: prevalence (epidemiology)
Answer: # existing cases/population at risk ...at a discrete point in time
Flashcard 3: meta-analysis (epidemiology)
Answer: Study that pools data from other studies and analyzes them in aggregate to achieve greater statistical power
Flashcard 4: incidence (epidemiology)
Answer: # new cases/population at risk ...over a specified time period (i.e. a compound rate)
Flashcard 5: What kind of study compares one group of people with disease to another group of people without disease and looks for an exposure or risk factor that explains the difference?
Answer: Case-control study
Flashcard 6: alternative hypothesis (H1)
Answer: Proposition of some difference between comparison groups
Flashcard 7: Explain how a case-control study works.
Answer: Compares a group of people with disease (cases) to a group of people without disease (controls) and looks for an exposure or risk factor that explains the difference.
Flashcard 8: Which direction does the tail go in a positive skew distribution? Negative skew?
Answer: positive - tail right negative - tail left
Flashcard 9: In a normal distribution, what is the relationship between mean, median, and mode?
Answer: mean = median = mode
Flashcard 10: Name and explain three common measures of central tendency of a distribution (biostatistics).
Answer: mean - average median - middle number in a ranked list mode - number that occurs most frequently
Flashcard 11: List five methods for reducing bias in clinical studies.
Answer: 1. Blinding 2. Placebo treatment 3. Randomization 4. Matching 5. Crossover
Flashcard 12: confounding bias
Answer: exists when a third factor is related to both the exposure and the outcome but NOT on the causal pathway (e.g. elective motorcycle training course appears to saves lives, but those likely to attend were already safer)
Flashcard 13: late-look bias
Answer: information gathered at an inappropriate time (e.g. telephone survey for a fatal disease)
Flashcard 14: Explain how a a cross-sectional study works.
Answer: Collects data from a group to assess prevalence of a disease at a discrete point in time.
Flashcard 15: What kind of study collects data from a group to assess prevalence of a disease at a discrete point in time?
Answer: Cross-sectional study
Flashcard 16: What is the unit for measuring outcomes in a cross-sectional study?
Answer: prevalence
Flashcard 17: sampling bias
Answer: subjects are not representative of general population (e.g. college students)
Flashcard 18: triple blinded with reference to study design
Answer: Patient, test administrator, and data analyzer are all blinded
Flashcard 19: How many clinical trial phases are there in the US?
Answer: 4
Flashcard 20: selection bias
Answer: nonrandom assignment of participants to study groups (e.g. loss to follow-up)
Flashcard 21: Selection bias, most commonly a type of _____, can be reduced via concealment
Answer: sampling bias
Extra: https://onlinemeded.org/spa/epidemiology-and-stats/bias/acquire?ref=anki
Flashcard 22: The _____ is a measure of the strength and direction of a linear relationship between 2 variables
Answer: correlation coefficient
Extra: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/biostatistics/videos/statistical-testing?index=5] https://onlinemeded.org?ref=anki
Flashcard 23: An unaffected individual (with unaffected parents) who has a sibling affected by an autosomal recessive condition has a(n) _____ chance of being a carrier for that condition
Answer: 2/3
Extra: https://onlinemeded.org/spa/genetics/modes-of-inheritance/acquire?ref=anki
Flashcard 24: An IDR of 0 implies that a disease is _____ in a population whereas an IDR of infinity implies instantaneous, universal effect on population
Answer: not occurring
Extra: https://onlinemeded.org?ref=anki
Flashcard 25: When using Hardy-Weinberg population genetics, p and q represent _____ frequencies
Answer: allelic
Extra: Watch Hardy Weinberg Population Genetics [https://dashboard.sketchy.com/study/medical/courses/medical-biochemistry/units/medical-biochemistry-clinical-genetics/videos/medical-biochemistry-clinical-genetics-population-genetics-hardy-weinberg-population-genetics?utm_source=anki&utm_medium=partnership&utm_campaign=february_update&utm_content=medical] Watch associated Bootcamp video [https://app.bootcamp.com/med-school/genetics/videos/basics-of-clinical-genetics?index=2] https://onlinemeded.org/spa/genetics?ref=anki
Flashcard 26: One assumption of Hardy-Weinberg population genetics is that _____ is not occurring
Answer: natural selection
Extra: Watch Hardy Weinberg Population Genetics [https://dashboard.sketchy.com/study/medical/courses/medical-biochemistry/units/medical-biochemistry-clinical-genetics/videos/medical-biochemistry-clinical-genetics-population-genetics-hardy-weinberg-population-genetics?utm_source=anki&utm_medium=partnership&utm_campaign=february_update&utm_content=medical] Watch associated Bootcamp video [https://app.bootcamp.com/med-school/genetics/videos/basics-of-clinical-genetics?index=2] https://onlinemeded.org/spa/genetics?ref=anki
Flashcard 27: _____ is when an external variable truly positively or negatively impacts the observed effect of a risk factor on disease status
Answer: Effect modification
Extra: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/biostatistics/videos/bias-and-study-errors?index=8] https://onlinemeded.org?ref=anki
Flashcard 28: A(n) _____ is similar to a Chi-square test in that it is used to compare categorical outcomes but in small populations
Answer: fisher's exact test
Extra: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/biostatistics/videos/statistical-testing?index=4] https://onlinemeded.org?ref=anki
Flashcard 29: For a chronic disease, how are prevalence and incidence related? _____
Answer: Prevalence > Incidence
Extra: https://onlinemeded.org?ref=anki
Flashcard 30: When using Hardy-Weinberg population genetics, p2, 2pq, and q2 represent _____ frequencies
Answer: genotypic
Extra: https://onlinemeded.org/spa/genetics?ref=anki
Flashcard 31: Measurement bias can be reduced by: - using a(n) _____ group - using objective and standardized methods of data collection
Answer: placebo
Extra: https://onlinemeded.org/spa/epidemiology-and-stats/bias/acquire?ref=anki
Flashcard 32: Which of the listed three demographics count the mortality of the following cancers as their top 3 most fatal in the United States? _____
Answer: Women
Extra: https://onlinemeded.org/spa/pulmonology/lung-cancer/acquire?ref=anki
Flashcard 33: Migration bias can be remedied with the _____ or the Best / Worst Case analysis
Answer: 5 and 20 rule
Extra: https://onlinemeded.org/spa/epidemiology-and-stats/bias/acquire?ref=anki
Flashcard 34: How are prevalence and incidence related? _____
Answer: Prevalence = Incidence X Duration
Extra: https://onlinemeded.org?ref=anki
Flashcard 35: Migration (attrition) bias is a form of selection bias that occurs when patients drop out of the study _____
Answer: prematurely
Extra: https://onlinemeded.org/spa/epidemiology-and-stats/bias/acquire?ref=anki
Flashcard 36: What equation is used to calculate allele frequency when using Hardy-Weinberg population genetics? _____
Answer: p + q = 1
Extra: Watch Hardy Weinberg Population Genetics [https://dashboard.sketchy.com/study/medical/courses/medical-biochemistry/units/medical-biochemistry-clinical-genetics/videos/medical-biochemistry-clinical-genetics-population-genetics-hardy-weinberg-population-genetics?utm_source=anki&utm_medium=partnership&utm_campaign=february_update&utm_content=medical] Watch associated Bootcamp video [https://app.bootcamp.com/med-school/genetics/videos/basics-of-clinical-genetics?index=2] https://onlinemeded.org/spa/genetics?ref=anki
Flashcard 37: Is IDR a dynamic measure? _____
Answer: Yes
Extra: https://onlinemeded.org?ref=anki
Flashcard 38: An Attack Rate is a special type of _____ that is the (# of people affected)/(# of people at risk at beginning of time period)
Answer: CIR
Extra: https://onlinemeded.org?ref=anki
Flashcard 39: What type of studies assess the frequency of a given characteristic and a given outcome using population data? _____
Answer: Ecological study
Extra: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/biostatistics/videos/research-study-designs?index=3] https://onlinemeded.org?ref=anki
Flashcard 40: Selection bias is an error introduced in _____ that occurs due to a(n) nonrandom sampling or treatment allocation of subjects
Answer: recruiting participants
Extra: https://onlinemeded.org/spa/epidemiology-and-stats/bias/acquire?ref=anki
Flashcard 41: Confounding Bias can be reduced by RANDOMIZATION, but other important interventions include: - _____ of exposure groups - crossover studies - restriction of characteristics - multiple / repeated studies
Answer: Matching / Stratification
Extra: https://onlinemeded.org/spa/epidemiology-and-stats/bias/acquire?ref=anki
Flashcard 42: If a treatment for a particular disease is developed the prolongs life but doesn't result in a cure... (options = incidence, prevalence, CFR, Mortality rate) - _____ is not affected - _____ increases, because affected live longer - _____ would depend on the stage of disease, but in general would decrease since less are likely to die during given time period - _____ in general would decrease since you would likely have less deaths in a given time period
Answer: Incidence
Extra: https://onlinemeded.org?ref=anki
Flashcard 43: In a Proportion of A/B, is A part of B? _____
Answer: Yes
Extra: https://onlinemeded.org?ref=anki
Flashcard 44: Measurement Bias and Procedure Bias differ in that the former is due to a(n) _____ procedure and the latter is due to a procedure applied in a(n) differential manner
Answer: flawed
Extra: https://onlinemeded.org/spa/epidemiology-and-stats/bias/acquire?ref=anki
Flashcard 45: Publication bias ("the file drawer effect") is a systematic error of _____ that results from only using published studies
Answer: meta-analysis
Extra: https://onlinemeded.org/spa/epidemiology-and-stats/bias/acquire?ref=anki
Flashcard 46: Is effect modification a form of bias? _____
Answer: No!
Extra: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/biostatistics/videos/bias-and-study-errors?index=8] https://onlinemeded.org?ref=anki
Flashcard 47: In order to determine a confidence interval of a(n) _____ at a given alpha value, the standard deviation, and sample size are also necessary
Answer: sample mean
Extra: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/biostatistics/videos/statistical-testing?index=7] https://onlinemeded.org/spa/epidemiology-and-stats/confidence-interval/acquire?ref=anki
Flashcard 48: An incidence density rate (IDR) measures the _____ of the disease in a population at a given point in time
Answer: instanteous rate of speed
Extra: https://onlinemeded.org?ref=anki
Flashcard 49: Assembly Bias occurs when groups of _____ assembled for prognostic study _____ in ways other than prognostic factors under study
Answer: exposed and non-exposed patients
Extra: https://onlinemeded.org/spa/epidemiology-and-stats/bias/acquire?ref=anki
Flashcard 50: What type of study design starts with cohort studies in which participants are followed over time, and participants who develop an outcome of interest become cases for a case-control study? _____
Answer: Nested case-control design
Extra: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/biostatistics/videos/research-study-designs?index=3] https://onlinemeded.org?ref=anki
Flashcard 51: A rate is a special type of _____ where the numerator is the # of affected individuals in a given time period and the denominator is the population at risk over the same time period
Answer: proportion
Extra: https://onlinemeded.org?ref=anki
Flashcard 52: Probability is the _____ of having an event where P=Odds/1+Odds
Answer: risk
Extra: https://onlinemeded.org?ref=anki
Flashcard 53: Randomization can be done in a blocked manner where randomization is done within _____ in order to ensure equal balance in number of treatment and control subjects throughout the study
Answer: blocks of 4-8 subjects
Extra: https://onlinemeded.org/spa/epidemiology-and-stats/bias/acquire?ref=anki
Flashcard 54: How big is the difference between probability and odds when the value of probability is small (<10%)? _____
Answer: Minimal Difference
Extra: https://onlinemeded.org?ref=anki
Flashcard 55: When using Hardy-Weinberg population genetics, the frequency of an X-linked recessive disease in males is equal to _____
Answer: q
Extra: Watch Hardy Weinberg Population Genetics [https://dashboard.sketchy.com/study/medical/courses/medical-biochemistry/units/medical-biochemistry-clinical-genetics/videos/medical-biochemistry-clinical-genetics-population-genetics-hardy-weinberg-population-genetics?utm_source=anki&utm_medium=partnership&utm_campaign=february_update&utm_content=medical] Watch associated Bootcamp video [https://app.bootcamp.com/med-school/genetics/videos/basics-of-clinical-genetics?index=2] https://onlinemeded.org/spa/genetics?ref=anki
Flashcard 56: IDR = (_____)/(sum of time periods for all disease free individuals at risk)
Answer: # of new cases
Extra: https://onlinemeded.org?ref=anki
Flashcard 57: _____% of colorectal cancers arise in patients with a positive family history
Answer: 25
Extra: Watch Colorectal Polyps & Cancer [https://dashboard.sketchy.com/study/medical/courses/medical-pathophysiology/units/medical-pathophysiology-gi/videos/medical-pathophysiology-gi-colorectal-and-anal-disorders-colorectal-polyps-and-cancer?utm_source=anki&utm_medium=partnership&utm_campaign=february_update&utm_content=medical] https://onlinemeded.org?ref=anki Atlas:
Flashcard 58: Can you use an ecological study to make conclusions regarding individuals within the populations of study? _____
Answer: No
Extra: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/biostatistics/videos/research-study-designs?index=3] https://onlinemeded.org?ref=anki
Flashcard 59: One assumption of Hardy-Weinberg population genetics is that there is _____ mating
Answer: completely random
Extra: Watch Hardy Weinberg Population Genetics [https://dashboard.sketchy.com/study/medical/courses/medical-biochemistry/units/medical-biochemistry-clinical-genetics/videos/medical-biochemistry-clinical-genetics-population-genetics-hardy-weinberg-population-genetics?utm_source=anki&utm_medium=partnership&utm_campaign=february_update&utm_content=medical] Watch associated Bootcamp video [https://app.bootcamp.com/med-school/genetics/videos/basics-of-clinical-genetics?index=2] https://onlinemeded.org/spa/genetics?ref=anki
Flashcard 60: Cumulative incidence = (# of new cases over a specific period) / (number of people at risk at the _____ of the period)
Answer: beginning
Extra: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/biostatistics/videos/risk-quantification?index=3] https://onlinemeded.org?ref=anki
Flashcard 61: For a short duration disease, how are prevalence and incidence related? _____
Answer: Prevalence ~ Incidence
Extra: https://onlinemeded.org?ref=anki
Flashcard 62: A meta-analysis improves the strength of evidence and _____ of study findings
Answer: generalizability
Extra: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/biostatistics/videos/statistical-testing?index=7] https://onlinemeded.org?ref=anki
Flashcard 63: One assumption of Hardy-Weinberg population genetics is that there is no net _____
Answer: migration
Extra: Watch Hardy Weinberg Population Genetics [https://dashboard.sketchy.com/study/medical/courses/medical-biochemistry/units/medical-biochemistry-clinical-genetics/videos/medical-biochemistry-clinical-genetics-population-genetics-hardy-weinberg-population-genetics?utm_source=anki&utm_medium=partnership&utm_campaign=february_update&utm_content=medical] Watch associated Bootcamp video [https://app.bootcamp.com/med-school/genetics/videos/basics-of-clinical-genetics?index=2] https://onlinemeded.org/spa/genetics?ref=anki
Flashcard 64: Lead-time bias can be reduced by measuring _____
Answer: "back-end" survival
Extra: https://onlinemeded.org/spa/epidemiology-and-stats/bias/acquire?ref=anki
Flashcard 65: Of the top 3 most fatal cancers in the United States, lung cancer is ranked _____ for incidence and _____ for mortality
Answer: 2nd
Extra: https://onlinemeded.org/spa/pulmonology/lung-cancer/acquire?ref=anki
Flashcard 66: Procedure bias is an error introduced in _____ that results from different groups being treated differently
Answer: performing the study
Extra: https://onlinemeded.org/spa/pediatrics/vaccinations/acquire?ref=anki
Flashcard 67: Exclusion criteria can result in _____ being compromised if too strict, maximizing Internal Validity
Answer: External Validity
Extra: https://onlinemeded.org/spa/epidemiology-and-stats/bias/acquire?ref=anki
Flashcard 68: In noncommunicable chronic diseases, the latent period may be _____
Answer: long
Extra: https://onlinemeded.org/spa/immunology?ref=anki
Flashcard 69: What type of disease prevention are vaccination and health promotion? _____
Answer: Primary
Extra: https://onlinemeded.org?ref=anki
Flashcard 70: The sickle cell (HbS) allele is carried by _____% of African Americans
Answer: 8 - 10
Extra: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/hematology-and-oncology/videos/normocytic-anemia?index=4] https://onlinemeded.org?ref=anki
Flashcard 71: Antigenic drift is associated with _____-demics
Answer: epi
Extra: Watch Influenzavirus (Orthomyxoviridae) [https://dashboard.sketchy.com/study/medical/courses/medical-microbiology/units/medical-microbiology-viruses/videos/medical-microbiology-viruses-rna-viruses-negative-sense-influenzavirus-orthomyxoviridae?utm_source=anki&utm_medium=partnership&utm_campaign=february_update&utm_content=medical] https://onlinemeded.org/spa/infectious-disease?ref=anki
Flashcard 72: Survival Cohort Bias is a special case of _____ where as survival cohort (available patients) is used instead of a(n) true inception cohort
Answer: assembly bias
Extra: https://onlinemeded.org/spa/epidemiology-and-stats/bias/acquire?ref=anki
Flashcard 73: Regarding the incidence of the three main types of skin cancer in the United States, _____ > _____ >> _____
Answer: Basal
Extra: Watch Malignant Melanoma [https://dashboard.sketchy.com/study/medical/courses/medical-pathophysiology/units/medical-pathophysiology-musculoskeletal-derm/videos/medical-pathophysiology-musculoskeletal-and-derm-derm-malignant-melanoma?utm_source=anki&utm_medium=partnership&utm_campaign=february_update&utm_content=medical] Watch associated Bootcamp video [https://app.bootcamp.com/med-school/dermatology/videos/malignant-skin-disorders?index=2] https://onlinemeded.org/spa/surgery-subspecialty/skin-cancer/acquire?ref=anki
Flashcard 74: When do you use a CIR? - when there is a(n) _____ population that is starting at a common point in time - when an outcome can occur only once - and when when disease event rates are relatively stable over time
Answer: fixed or closed
Extra: https://onlinemeded.org?ref=anki
Flashcard 75: Lung cancer is the _____ most common cancer by incidence
Answer: 2nd
Extra: https://onlinemeded.org/spa/pulmonology/lung-cancer/acquire?ref=anki
Flashcard 76: Odds are the _____ of the probability of having an event to the probability of not having
Answer: ratio
Extra: https://onlinemeded.org?ref=anki
Flashcard 77: One assumption of Hardy-Weinberg population genetics is that no _____ have occurred at the locus
Answer: mutations
Extra: Watch Hardy Weinberg Population Genetics [https://dashboard.sketchy.com/study/medical/courses/medical-biochemistry/units/medical-biochemistry-clinical-genetics/videos/medical-biochemistry-clinical-genetics-population-genetics-hardy-weinberg-population-genetics?utm_source=anki&utm_medium=partnership&utm_campaign=february_update&utm_content=medical] Watch associated Bootcamp video [https://app.bootcamp.com/med-school/genetics/videos/basics-of-clinical-genetics?index=2] https://onlinemeded.org/spa/genetics?ref=anki
Flashcard 78: Is probability a proportion or a ratio? _____
Answer: Proportion
Extra: https://onlinemeded.org?ref=anki
Flashcard 79: A study finds the correlation coefficient between plasma homocysteine levels and folic acid intake to be -.8 (p <0.01). How much of the variability in plasma homocysteine levels is explained by folic acid intake? _____
Answer: 64%
Extra: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/biostatistics/videos/risk-quantification?index=10] https://onlinemeded.org?ref=anki
Flashcard 80: This is an example of a(n) _____ study
Answer: cross-over
Extra: https://onlinemeded.org/spa/epidemiology-and-stats/bias/acquire?ref=anki
Flashcard 81: Clostridium botulinum spore inhalation has a particularly high incidence in _____, Pennsylvania, and Utah
Answer: California
Extra: https://onlinemeded.org?ref=anki
Flashcard 82: An observer expecting treatment group to show signs of recovery is more likely to document positive outcomes; this is an example of the _____ effect
Answer: Pygmalion
Extra: https://onlinemeded.org/spa/epidemiology-and-stats/bias/acquire?ref=anki
Flashcard 83: Accuracy is decreased by _____ error in a test
Answer: systematic
Extra: https://onlinemeded.org?ref=anki
Flashcard 84: A(n) _____ study refers to the additional blinding of the researchers analyzing the data
Answer: triple-blind
Extra: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/biostatistics/videos/research-study-designs?index=6] https://onlinemeded.org?ref=anki
Flashcard 85: Patients in treatment group spend more time in highly specialized hospital units is an example of which type of bias? _____
Answer: Procedure
Extra: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/biostatistics/videos/bias-and-study-errors?index=4] https://onlinemeded.org/spa/epidemiology-and-stats/bias/acquire?ref=anki
Flashcard 86: What equation is used to calculate odds ratio using the table below? _____
Answer:
Extra: https://onlinemeded.org/spa/epidemiology-and-stats/risk/acquire?ref=anki
Flashcard 87: A slowly progressive cancer is more likely detected by a screening test than a rapidly progressive cancer. This is an example of _____ bias
Answer: length/lag-time
Extra: https://onlinemeded.org/spa/epidemiology-and-stats/bias/acquire?ref=anki
Flashcard 88: The exposed group undergoes increased monitoring leading to increased probability of identifying a disease = _____ bias
Answer: surveillance
Extra: https://onlinemeded.org?ref=anki
Flashcard 89: The power of a study is calculated by _____
Answer: 1 - β
Extra: https://onlinemeded.org/spa/epidemiology-and-stats/hypothesis-testing/acquire?ref=anki
Flashcard 90: The _____ is a statistical test used to compare the difference between a continuous outcome variable of 2 predictor group(s) at 1 point(s) in time
Answer: unpaired two-sample t-test
Extra: https://onlinemeded.org?ref=anki
Flashcard 91: Patients lost to follow up is a type of _____ bias
Answer: selection
Extra: https://onlinemeded.org?ref=anki
Flashcard 92: What kind of study design is shown below? _____
Answer: Factorial design
Extra: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/biostatistics/videos/research-study-designs?index=6] https://onlinemeded.org?ref=anki
Flashcard 93: If the 95% CI for odds ratio or relative risk includes 1, H0 _____ rejected
Answer: is not
Extra: https://onlinemeded.org?ref=anki
Flashcard 94: What kind of study design is this? _____
Answer: Parallel study
Extra: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/biostatistics/videos/research-study-designs?index=6] https://onlinemeded.org?ref=anki
Flashcard 95: _____ = least affected by outliers _____ = most affected by outliers
Answer: Mode
Extra: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/biostatistics/videos/statistical-distributions?index=2] https://onlinemeded.org?ref=anki
Flashcard 96: Gene X is known as a(n) _____
Answer: effect modifier
Extra: https://onlinemeded.org/spa/epidemiology-and-stats/bias/acquire?ref=anki
Flashcard 97: What type of study has a population as the unit of analysis (rather than individual)? _____
Answer: Ecological study
Extra: https://onlinemeded.org?ref=anki
Flashcard 98: Z-score = and 1 _____
Answer: 1 SD above the mean
Extra: https://onlinemeded.org?ref=anki
Flashcard 99: _____
Answer:
Extra: https://onlinemeded.org?ref=anki
Flashcard 100: What kind of bias is this? _____
Answer: Selection bias
Extra: https://onlinemeded.org/spa/epidemiology-and-stats/bias/acquire?ref=anki
Flashcard 101: Can you typically calculate the risk ratio in case-control studies? _____
Answer: NO - must use odds ratio
Extra: https://onlinemeded.org/spa/epidemiology-and-stats/risk/acquire?ref=anki
Flashcard 102: What is the variance for a standard deviation of 10? _____
Answer: 10^2=100
Extra: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/biostatistics/videos/statistical-distributions?index=3] https://onlinemeded.org?ref=anki
Flashcard 103: In regards to the Pearson Correlation Coefficient, the closer the absolute r value is to _____, the stronger the correlation between 2 variables
Answer: 1
Extra: https://onlinemeded.org?ref=anki
Flashcard 104: Absolute Risk Reduction = _____ Relative Risk Reduction = _____ Number needed to treat = _____
Answer: 50 - 30 = 20%
Extra: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/biostatistics/videos/risk-quantification?index=10] https://onlinemeded.org/spa/epidemiology-and-stats/bias/acquire?ref=anki
Flashcard 105: The Women's Health Initiative (WHI) Study had poor _____ validity due to _____
Answer: external
Extra: https://onlinemeded.org/spa/gynecology/menopause/acquire?ref=anki
Flashcard 106: If the 95% CI for a mean difference between 2 variables includes 0, then there _____ a significant difference between the two groups
Answer: is NOT
Extra: https://onlinemeded.org?ref=anki
Flashcard 107: For _____ diseases, OR = RR. In these cases, case-control studies can actually calculate _____
Answer: rare (< 10%)
Extra: https://onlinemeded.org/spa/epidemiology-and-stats/risk/acquire?ref=anki
Flashcard 108: Calculate the 95% confidence interval (p<.05): Sample Mean = 200 Standard Error = 5 _____
Answer: For 95%, Z=1.96: CI = 200 +/- 1.96(5)
Extra: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/biostatistics/videos/statistical-testing?index=7] https://onlinemeded.org?ref=anki
Flashcard 109: Which of the results above show confounding variable and which shows effect modification? _____
Answer: 1 = effect modification (effect maintained when gene x present) 2 = confounding (elimination of effect when risk stratify into smokers and non-smokers)
Extra: https://onlinemeded.org/spa/epidemiology-and-stats/bias/acquire?ref=anki
Flashcard 110: Exposures that happen long before disease assessment may cause the study to miss diseased patients who die earlier = _____ bias
Answer: neyman
Extra: https://onlinemeded.org?ref=anki
Flashcard 111: Sampling bias is an example of _____ bias
Answer: selection
Extra: https://onlinemeded.org/spa/epidemiology-and-stats/bias/acquire?ref=anki
Flashcard 112: _____ occurs when the risk factor-disease relationship is obscured by an external variable associated with both the risk exposure and disease
Answer: Confounding
Extra: https://onlinemeded.org/spa/epidemiology-and-stats/bias/acquire?ref=anki
Flashcard 113: Subjects over/under report exposure history due to perceived social stigma = _____ bias
Answer: reporting
Extra: https://onlinemeded.org?ref=anki
Flashcard 114: Calculate the standard error: Variance = 100 n=25 _____
Answer: SE=sqrt (100/25)= 2
Extra: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/biostatistics/videos/statistical-distributions?index=3] https://onlinemeded.org?ref=anki
Flashcard 115: The _____ is a statistical test used to compare the difference between a continuous outcome variable of 1 predictor group(s) at 2 point(s) in time
Answer: paired two-sample t-test
Extra: https://onlinemeded.org?ref=anki
Flashcard 116: Breast/prostate cancer is the _____ most common cancer by mortality
Answer: 2nd
Flashcard 117: What equation is used to calculate allele frequency when using Hardy-Weinberg population genetics?_____
Answer: p + q = 1
Flashcard 118: Lung cancer is the _____ most common cancer by incidence
Answer: 2nd
Flashcard 119: _____ studies are observational studies that compare a group of people with disease to a group without disease
Answer: Case-control
Flashcard 120: One assumption of Hardy-Weinberg population genetics is that _____ is not occuring
Answer: natural selection
Flashcard 121: What type of bias occurs when patients change their behavior in response to their awareness of being observed? _____
Answer: Hawthorne bias
Flashcard 122: Prevalence is _____ than incidence for chronic diseases (e.g. diabetes)
Answer: greater
Flashcard 123: For a chronic disease, how are prevalence and incidence related? _____
Answer: Prevalence > Incidence
Flashcard 124: Why does Generalizability bias matter? _____
Answer: Because patients in tertiary centers are usually highly selected
Flashcard 125: Cardiovascular disease (CVD) is the _____ leading cause of death in adults
Answer: 1st
Flashcard 126: Odds are the _____ of the probability of having an event to the probability of not having
Answer: ratio
Flashcard 127: Accidents are the _____ leading cause of death in children
Answer: 1st
Flashcard 128: In the United States, cancer is the second leading cause of death in which of the following age groups?_____
Answer:
Flashcard 129: What is the most common cause of death in from 1 - 44 years old? _____
Answer: Unintentional injury
Flashcard 130: Are case-control studies useful for measuring incidence and/or prevalence? _____
Answer: Neither
Flashcard 131: What type of error is stating that there is NO effect when one DOES exists?_____
Answer: Type II (false-negative error)
Flashcard 132: If 2% of patients who receive a flu shot develop the flu, while 8% of unvaccinated patients develop the flu, absolute risk reduction is _____
Answer: 6% (.06)
Flashcard 133: An LOD score less than _____ indicates no linkage
Answer: -2
Flashcard 134: _____ studies are observational studies that compare siblings raised by biological versus adoptive parents
Answer: Adoption
Flashcard 135: Linkage disequlibrium is measured in a _____, not in a family
Answer: population
Flashcard 136: What is the relationship between prevalence and incidence?prevalence / (1 - prevalence) = _____
Answer: incidence * average duration of disease
Flashcard 137: What is the relationship between the mean, median, and mode in a negatively skewed distribution?_____
Answer: Mean < median < mode
Flashcard 138: What type of disease prevention is screening for disease (individual or community)?_____
Answer: Secondary
Flashcard 139: One assumption of Hardy-Weinberg population genetics is that there is _____ mating
Answer: completely random
Flashcard 140: What type of study design starts with cohort studies in which participants are followed over time, and participants who develop an outcome of interest become cases for a case-control study?_____
Answer: Nested case-control design
Flashcard 141: Is the CFR the same as the Mortality Rate? _____
Answer: No
Flashcard 142: Are cross-sectional surveys useful for measuring incidence and/or prevalence? _____
Answer: Prevalence
Flashcard 143: A meta-analysis improves the strength of evidence and _____ of study findings
Answer: generalizability
Flashcard 144: What type of bias is caused by early detection being confused with increased survival? _____
Answer: Lead-time bias
Flashcard 145: Meckel diverticulum is two times more likely to occur in _____ (gender)
Answer: males
Flashcard 146: _____ is responsible for most of the public exposure to ionizing radiation
Answer: Radon
Flashcard 147: What statistical test is used to check differences between the means of TWO groups? _____
Answer: t-test
Flashcard 148: _____ prevalence refers to the amount of an existing condition present in a population during a particular time period
Answer: Period
Flashcard 149: _____ are a range of values within which the true mean of the population is expected to fall, with a specified probability (usually 95%)
Answer: Confidence intervals
Flashcard 150: What demographic is associated with pseudofolliculitis barbae?_____
Answer: African-American males
Flashcard 151: The power of a study is increased with _____ precision of measurement
Answer: increased
Flashcard 152: What type of error is stating that there is an effect when none exists?_____
Answer: Type I (false-positive error)
Flashcard 153: Confounding bias occurs when the exposure-disease relationship is muddled by the effect of an extraneous factor that is associated with both exposure and disease and _____ on the causal pathway
Answer: is NOT
Flashcard 154: _____ describes the tendency of alleles at two loci on the same chromosome to be inherited together more or less often than expected by chance
Answer: Linkage disequilibrium
Flashcard 155: Precision may also be referred to as _____
Answer: reliability
Flashcard 156: When using Hardy-Weinberg population genetics, the frequency of an X-linked recessive disease in males is equal to _____
Answer: q
Flashcard 157: The statistical power of a study is calculated by _____
Answer: 1- beta
Flashcard 158: Lead-time bias can be reduced by measuring _____
Answer: "back-end" survival
Flashcard 159: What selection bias occurs when specifically selecting patients from a hospital? _____
Answer: Berkson bias
Flashcard 160: When using Hardy-Weinberg population genetics, p2, 2pq, and q2 represent _____ frequencies
Answer: genotypic
Flashcard 161: The incidence of pancreatic cancer in women has slowly _____ over the last century
Answer: increased
Flashcard 162: The sickle cell (HbS) allele is carried by _____% of African Americans
Answer: 8 - 10
Flashcard 163: How are prevalence and incidence related? _____
Answer: Prevalence = Incidence X Duration
Flashcard 164: What type of study uses subjects as their own controls?_____
Answer: Crossover studies
Flashcard 165: Which measure of dispersion measures the variability of a set of sample means around the true population mean? _____
Answer: Standard error
Flashcard 166: The power of a study is increased with _____ expected effect size
Answer: increased
Flashcard 167: Outbreaks of Rickettsia prowazekii are commonly seen in _____
Answer: Military camp recruits and prisoners of war
Flashcard 168: The number needed to harm (NNH) is equal to _____
Answer: 1/AR
Flashcard 169: Can you use an ecological study to make conclusions regarding individuals within the populations of study?_____
Answer: No
Flashcard 170: What statistical test is used to test the association between two or more categorical variables? _____
Answer: Chi-squared
Flashcard 171: Concealment is critical in preventing _____
Answer: selection bias
Flashcard 172: Increased precision is associated with _____ standard deviation
Answer: decreased
Flashcard 173: Which of the listed three demographics count the mortality of the following cancers as their top 3 most fatal in the United States?_____
Answer: Children (age 0-14) (Men, Women, or Children (age 0-14)?)
Flashcard 174: _____ risk reduction is the difference in risk attributable to an intervention compared to a control
Answer: Absolute
Flashcard 175: What type of study is at the pinnacle of the hierarchy of medical evidence?_____
Answer: Meta analysis
Flashcard 176: The Mortality Rate measures the _____ due to a specific disease in a population at risk
Answer: speed of death
Flashcard 177: Multiple sclerosis is more commonly seen in caucasians in regions _____ the equator (towards or away from)
Answer: away from
Flashcard 178: What type of bias occurs when patients do not get studied because they die?_____
Answer: Late-look Bias
Flashcard 179: What country consumes a large amount of smoked meats in their diet, resulting high rates of intestinal gastric cancer?_____
Answer: Japan
Flashcard 180: The probability of making a type 1 error is represented by _____
Answer: alpha
Flashcard 181: _____ studies are observational studies that compare the frequency with which monozygotic and dizygotic twins develop the same disease
Answer: Twin concordance
Flashcard 182: Behcet syndrome has a high incidence in those of _____ / East Mediterranean descent
Answer: Turkish
Flashcard 183: Mini-epidemics of Pityriasis Rosea will often occur among _____
Answer: young adults
Flashcard 184: _____ prevalence refers to the amount of an existing condition present in a population at a single point in time
Answer: Point
Flashcard 185: The probability of making a type 2 error is represented by _____
Answer: beta
Flashcard 186: Mutation-selection equilibrium is an equilibrium that occurs when the rate of deleterious allele mutations _____ the rate at which the deleterious alleles are eliminated by selection
Answer: equals
Flashcard 187: What type of non-normal distribution is suggestive of two different populations (e.g. slow vs. fast acetylators)? _____
Answer: Bimodal
Flashcard 188: For rare diseases (low prevalence), _____ approximates relative risk
Answer: odds ratio
Flashcard 189: Which measure of dispersion measures the variability in a set of values? _____
Answer: Standard deviation
Flashcard 190: When using Hardy-Weinberg population genetics, p and q represent _____ frequencies
Answer: allelic
Flashcard 191: One assumption of Hardy-Weinberg population genetics is that no _____ have occurred at the locus
Answer: mutations
Flashcard 192: One assumption of Hardy-Weinberg population genetics is that there is no net _____
Answer: migration
Flashcard 193: As the sample size increases, the standard error _____
Answer: decreases
Flashcard 194: The _____ is a measure of the strength and direction of a linear relationship between 2 variables
Answer: correlation coefficient
Flashcard 195: In a Proportion of A/B, is A part of B? _____
Answer: Yes
Flashcard 196: When using Hardy-Weinberg population genetics, the frequency of a carrier of a recessive disease is equal to _____
Answer: 2pq
Flashcard 197: A method of statistical analysis that pools summary data (ex. means, RRs) from multiple studies for a more precise estimate of the size of an effect is known as _____
Answer: meta-analysis
Flashcard 198: What equation is used to calculate genotypic frequency when using Hardy-Weinberg population genetics?_____
Answer: p2 + 2pq + q2 = 1
Flashcard 199: Recall bias can be reduced by _____ time from exposure to follow-up
Answer: decreasing
Flashcard 200: Non-alcoholic steatohepatitis is seen with a high prevalence in the _____ male population
Answer: Native American
Flashcard 201: If 2% of patients who receive a flu shot develop the flu, while 8% of unvaccinated patients develop the flu, relative risk reduction is _____
Answer: 0.75
Flashcard 202: Which type of observational study is best for studying rare diseases? _____
Answer: Case-control studies
Flashcard 203: How big is the difference between probability and odds when the value of probability is small (<10%)? _____
Answer: Minimal Difference
Flashcard 204: Is effect modification a form of bias?_____
Answer: No!
Flashcard 205: Prevalence is _____ to incidence for short duration disease (e.g. chronic cold)
Answer: similar
Flashcard 206: What statistical test is used to check differences between the means of THREE or more groups? _____
Answer: Analysis of variance (ANOVA)
Flashcard 207: How does the width of a 95% confidence interval change with a decreased sample size? _____
Answer: Increased width
Flashcard 208: What type of bias is likely to occur in when asking patients with disease versus patients without disease about prior risk factors? _____
Answer: Recall bias
Flashcard 209: Case-control studies are almost always _____-spective
Answer: retro
Flashcard 210: What is a source of hepatitis A virus in developing countries?_____
Answer: Contaminated water
Flashcard 211: _____ is used to model the linear relationship between a dependent variable and an independent variable
Answer: Linear regression
Flashcard 212: Assembly Bias is a type of selection bias instead of a confounding bias because it occurs during the _____
Answer: selection process of subjects
Flashcard 213: What type of disease prevention is treatment to reduce complications from disease that will have long-term effects?_____
Answer: Tertiary
Flashcard 214: Accuracy may also be referred to as _____
Answer: validity
Flashcard 215: What equation is used to calculate odds ratio using the table below?_____
Answer: OR = (A/C) / (B/D) = (A*D) / (B*C)
Flashcard 216: In the United States, Cancer is the _____ leading cause of death
Answer: second
Flashcard 217: An LOD score greater than _____ indicates linkage
Answer: 3
Flashcard 218: Increased precision is associated with _____ statistical power (1 - )
Answer: increased
Flashcard 219: What is the relationship between the mean, median, mode in a positively skewed distribution?_____
Answer: Mean > median > mode
Flashcard 220: _____ is the trueness of test measurements
Answer: Accuracy (validity)
Flashcard 221: What is the equation for standard error? _____
Answer:
Flashcard 222: If the confidence interval does not include the null value, the result is statistically _____
Answer: significant
Flashcard 223: What selection bias occurs when specifically selecting healthy people? _____
Answer: Healthy worker effect
Flashcard 224: In a Ratio of A/B, is A part of B? _____
Answer: No
Flashcard 225: Patients typically get exposed to _____ radiation via exposure to the sunlight
Answer: Non-Ionizing
Flashcard 226: What type of bias is caused by increased detection of diseases (e.g. cancer) with a more benign course? _____
Answer: Length-time bias
Flashcard 227: _____ surveys are observational studies that compare a frequency of disease and frequency of risk related factors at one time point
Answer: Cross-sectional
Flashcard 228: The power of a study is increased with _____ sample size
Answer: increased
Flashcard 229: Is probability a proportion or a ratio? _____
Answer: Proportion
Flashcard 230: What type of studies assess the frequency of a given characteristic and a given outcome using population data?_____
Answer: Ecological study
Flashcard 231: For a short duration disease, how are prevalence and incidence related? _____
Answer: Prevalence ~ Incidence
Flashcard 232: When using Hardy-Weinberg population genetics, the frequency of an X-linked recessive disease in females is equal to _____
Answer: q2
Flashcard 233: A _____ is similar to a Chi-square test in that it is used to compare categorical outcomes but in small populations.
Answer: fisher's exact test
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