Question

4. In a study of 500 children, 238 were randomly selected to get a new vaccine.

The other 262 children were randomly selected to receive a placebo. After 5
years, 22 of the 238 vaccinated children had been infected with malaria; while
28 of the 262 children who received the placebo had been infected. Is this an
experiment or observational study?
A Experiment
B) Observational Study
C) Both and experiment and observational study
D) Neither

Answer 1

The study is an experiment because it involves the active application of a treatment to an experimental group and comparison with a control group receiving a placebo.

Step-by-step explanation:

The study of 500 children, in which 238 were randomly selected to get a new vaccine and the other 262 children to receive a placebo, would be considered an experiment.

This is because the researcher is actively applying a treatment (the vaccine) to the experimental group and comparing their outcomes with a control group that received a placebo.

The hallmark of an experiment, as opposed to an observational study, is this deliberate manipulation of one group and comparison with a control group.

Jonas Salk's polio vaccine trial is an example of a well-designed experiment: participants were randomized, a control group was used, and the trial was blind to prevent bias, setting the standard for clinical trials.