COMLEX II: Statistics Exam Questions And Complete Solutions

How do you calculate relative risk? - Correct Answer [A/(A+B)]/[C/(C+D)] expresses the risk of disease in people exposed to a given factor What type of study uses relative risk to evaluate conclusions? - Correct Answer cohort study what type of study uses odds ratio to evaluate conclusions? - Correct Answer case-control study what is the difference between case-control and cohort studies? - Correct Answer cohort study: examines a group of subjects exposed to a given situation or factor; usually prospective case-control: retrospective comparison of patients with a disease to healthy controls; frequency of certain exposures in both groups is considered How do you calculate the odds ratio? - Correct Answer (A/B)/(C/D) expresses the odds of exposure among patients with a disease compared with odds of exposure among patients wo a disease What does an RR val of 1 mean? - Correct Answer RR = 1 means that there is NO relationship between exposure and disease What does RR 1 mean? - Correct Answer RR 1 suggests a negative relationship between exposure and disease (exposure prevents disease) What does RR 1 mean? - Correct Answer RR1 suggests a positive relationship between exposure and disease (exposure increases risk of dz) When are OR and RR equivalent? - Correct Answer OR is an estimate of RR when the prevalence is low What is the null hypothesis? - Correct Answer states that no association exists between exposure and disease or between treatment and response What is a Type I error? - Correct Answer rejection of the null hypothesis even though it is true (false positive) What is a Type II error? - Correct Answer not rejecting the null hypothesis even though it is false (false negative); examp