The Wall Street Journal CEO Compensation Study analyzed CEO pay from many U.S. companies with fiscal year 2008 revenue of at least $5 billion that filed their proxy statements between October 2008 and March 2009. The data are in the file P02_30.xlsx.
a. Create a new column, Total, that is the sum of columns D and E.
b. After combining Telecommunications and Technology into a single company type, there are nine company types. For each of these, find a 95% confidence interval for the difference between the mean of Total for that company type and mean of Total for all other company types. Comment on what these nine confidence intervals indicate about CEO pay in different industries.