The Colleges Health Center wants to see if putting antibacte

The College\'s Health Center wants to see if putting antibacterial soap in the dormitory bath rooms will reduce the number of visits to the infirmary. In all 2,000 students spanning over all twenty residence halls participated. Half the dormitories chosen at random were supplied with the special soap; the remaining ones were supplied with regular soap. At the end of the semester, the two groups of students were compared using the number of visits to the infirmary per person per semester.

a) Why is this example of an experimental study and not an example of an observational study?

b) Are the observational units and the experimental units the same?

c) Name at least two blocking factors that could exist in this experimental study.

d) Name at least three variables that would appear in the sample dataset.

e) Name at least one confounding variable that can exist to debate the validity of the findings.

Solution

a) Because the study is about the effect of the soap in reducing the number of visits to the infirmary.

b) experimental units and observational units are not same

c) The blocking factors may be the residence halls and number of students in a group

d) The three variables are Group,Type of the soap, number of visits to the infirmary

e) Group may be confounded