Sample size calculation for different study designs — Flashcards

Flashcard 1: _____ surveys are observational studies that compare a frequency of disease and frequency of risk related factors at one time point

Answer: Cross-sectional

Flashcard 2: Are cohort studies useful for measuring incidence and/or prevalence? _____

Answer: Incidence

Flashcard 3: The power of a study is increased with _____ precision of measurement

Answer: increased

Flashcard 4: What is the t-test used for? (biostatistics)

Answer: Compare means of two groups. mnemonic: Mr. T is mean.

Flashcard 5: "β" with reference to statistical error

Answer: the probability of making a Type II statistical (false negative) error

Flashcard 6: power (epidemiology)

Answer: probability of detecting a differential effect if it is actually present

Extra: power = (1-β)

Flashcard 7: What is the relationship between standard error of the mean and standard deviation?

Answer: SEM = SD / √n (Standard Error of the Mean = Standard Deviation / √Sample size)

Flashcard 8: In a normal distribution, how many data points fall within three standard deviations from the mean?

Answer: 99.7%

Flashcard 9: In a normal distribution, how many data points fall within two standard deviations from the mean?

Answer: 95%

Flashcard 10: In a normal distribution, how many data points fall within one standard deviation from the mean?

Answer: 68%