Chapter 12.2, Problem 51E

(a)

To determine

Find: the two minimal reasons that they believe they have made this decision.

Explanation of Solution

The 1100 teachers are in 40 separate sessions and therefore it would take a lot of time and resources to track down any single teacher (present in the sample).

Using cluster sampling for each single session as a cluster will be simpler, because all teachers from a couple of these clusters would be in the study. This method of sampling would be much simpler than simply a random sample.

(b)

To determine

To find out: the sampling approach will suggest taking this probability into account and describing a statistical advantage of this approach over an SRS.

Explanation of Solution

Teachers on every subject area are required to be included in the sample, and then use stratified random sampling is best.

Stratified random sampling is drawing simple random samples from independent subgroups, In this case, in which each subject area is the subgroups.

This allows to compare the subject area with the proportion of tattoo-bearing teachers.