Question

To study the effectiveness of a vaccine, children in grades 1-3 were randomly assigned to one of three groups: inoculation, placebo, and no inoculation. Two years later, the three groups were compared for the incidence of the disease. A. Ecological B. Experimental C. Case-control D. Cross-sectional E. Descriptive F. Cohort

Answer 1

Result:

To study the effectiveness of a vaccine, children in grades 1-3 were randomly assigned to one of three groups: inoculation, placebo, and no inoculation. Two years later, the three groups were compared for the incidence of the disease.

A. Ecological

Answer: B. Experimental

C. Case-control

D. Cross-sectional

E. Descriptive

F. Cohort

Experimental studies involve the random assignment of -participants into different groups (e.g. experimental, control) in order to determine the causal effect of a inoculation (independent variable) on incidence of the disease (dependent variable).