An investigator is measuring the blood calcium level in a sample of female cross country runners and a control group of sedentary females. If she would like to compare the means of the two groups, which statistical test should she use?
AChi-square test
BLinear regression
Ct-test
DANOVA (Analysis of Variance)
EF-test
An 11-month-old boy is brought to a pediatrician by his parents for evaluation of vomiting and watery diarrhea over the last day. The mother informs the pediatrician that the boy had consumed an apple bought from a fruit vendor on the previous day, but that otherwise there has been no recent change in his diet. There is no history of blood in the stool, flatulence, irritability, or poor appetite. There is no history of recurrent or chronic diarrhea or any other gastrointestinal symptoms. On physical examination, his temperature is 37.6°C (99.6°F), pulse is 120/min, respirations are 24/min, and blood pressure is 92/60 mm Hg. General examination reveals a playful infant with normal skin turgor and no sunken eyes. The pediatrician explains to the parents that he most likely has acute gastroenteritis and that no specific medication is indicated at present. He also instructs the parents about his diet during the illness and reviews the danger signs of dehydration. He suggests a follow-up evaluation after 48 hours or earlier if any complications arise. Which of the following dietary recommendations did the pediatrician make?
APlenty of juices and carbonated sodas
BAge-appropriate diet
CDiluted formula milk
DLactose-free diet
EBRAT diet
Study X examined the relationship between coffee consumption and lung cancer. The authors of Study X retrospectively reviewed patients' reported coffee consumption and found that drinking greater than 6 cups of coffee per day was associated with an increased risk of developing lung cancer. However, Study X was criticized by the authors of Study Y. Study Y showed that increased coffee consumption was associated with smoking. What type of bias affected Study X, and what study design is geared to reduce the chance of that bias?
AObserver bias; double blind analysis
BSelection bias; randomization
CLead time bias; placebo
DMeasurement bias; blinding
EConfounding; randomization
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