Chapter 6.1, Problem 6.8E

To determine

To discuss how each of the three principles of experimental design was addressed in Physicals’ health study.

Explanation of Solution

The first principle is replication. By picking $22,071$ males as experimental units, researchers are ensuring that each of their two treatments are replicated over $11,000$ times. The second principle is randomization. The previous problem states that the males were randomly assigned to the two treatments. The third principle is local control, which is best addressed by the placebo, since a placebo will show whether aspirin itself has any effect.