CH 7

The Excel file contains the data from a 2008 Wall Street Journal survey of chief executive officers from 381 of the largest US public companies. Consider the data set to be our population.

1) Calculate the mean, median, and standard deviation of the salaries earned by the CEOs in 2008.

2) Choose a random sample of 25 CEOs and their salaries. You may use either of the two methods discussed in class. DO NOT simply take the first 25 observations in the data set.

3) For your sample, calculate the following:

· Mean

· Median

· Standard Deviation

· Standard Error

· Confidence Interval Estimate

4) How do the first three sample statistics compare to the mean, median, and standard deviation of the entire population of 381? Does the population mean fit within your confidence interval estimate?

The purpose of this question is two-fold: first, to give you practice creating a random sample and second, to let you see sampling error first-hand. If your sample actually gives you the same mean, median, and standard deviation as the entire data set, it's time to buy some lottery tickets.