In a study of stress levels in U.S. Army recruits stationed in Iraq, researchers obtained a complete list of the names of recruits in Iraq at the time of the study. They listed the recruits alphabetically and then numbered them consecutively. One hundred random numbers between one and the total number of recruits were then generated using a random-number generator on a computer. The 100 recruits whose numbers corresponded to those generated by the computer were interviewed for the study.

a. What is the population of interest in this study?

b. The 100 recruits interviewed were randomly sampled as described. Is the sample affected by sampling error? Explain.

c. What are the main advantages of random sampling in this example?

d. What effect would a larger sample size have had on sampling error?