Here is a sample of ACT scores (average of the Math, English, Social Science, and Natural Science scores) for students taking college freshman calculus:

24.00 28.00 27.75 27.00 24.25 23.50 26.25 24.00 25.00. 30.00 23.25 26.25 21.50 26.00 28.00 24.50 22.50 28.25 21.25 19.75

a. Calculate a two-sided 95% confidence interval for the population mean

b. The university ACT average for entering freshmen that year was about 21. Are the calculus students better than average, as measured by the ACT?