A Statistical Analysis In the article “ Robbing Banks ” Reilly et al. studied several aspects of bank robberies. As these researchers state, “Robbing a bank is the staple crime of thrillers, movies and newspapers. But . . . bank robbery is not all it is cracked up to be.” The researchers concentrated on the factors that determine the amount of proceeds from bank robberies, and thus were able to work out both the economics of attempting one and of preventing one. In particular, the researchers revealed that the return on an average bank robbery per person per raid is modest indeed—so modest that it is not worthwhile for the banks to spend too much money on such preventative measures as fast-rising screens at tellers’ windows. The researchers obtained exclusive data from the British Bankers’ Association. In one aspect of their study, they analyzed the data from a sample of 364 bank raids over a several-year period in the United Kingdom.

The following table repeats a portion of Table of the article.

Variable Mean Std. dev. Amount stolen (pounds sterling) 20,330.5 53,510.2 Number of bank staff present 5.417 4.336 Number of customers present 2.000 3.684 Number of bank raiders 1.637 0.971 Travel time, in minutes from bank to nearest police station 4.557 4.028 After studying point estimates and confidence intervals in this chapter, you will be asked to use these summary statistics to estimate the (population) means of the variables in the table.

a. The statistical software package of your choice and then obtain and interpret a 95% confidence interval for the mean high school percentile of all UWEC undergraduate students. Interpret your result.

b. The (population) mean of the variable under consideration is unknown. However, in this case, we actually do have the population data, namely, in the Focus database (Focus). If you’re statistical software package will accommodate the entire Focus database, open that worksheet and then obtain the mean high school percentile of all UWEC undergraduate students.