An associate dean of a university wishes to compare the mean on the standardized final exams in microeconomics and macroeconomics. He has access to a random sample of 40 scores from each of these two courses. A portion of the data is shown below; the complete data set, labeled Economics, can be found on the text website.
Micro Macro
85......... 48
78......... 79
: ......... :
75......... 74

a. Use Excel to construct 95% confidence intervals for the mean score in microeconomics and the mean score in macroeconomics.
b. Explain why the widths of the two intervals are different.