For the 25 and over sample, purchase amounts average $ 146.30 with a standard deviation of $

Question:

For the 25 and over sample, purchase amounts average $ 146.30 with a standard deviation of $ 27.00.
a. Build and interpret the 95% confidence interval estimate appropriate here.
b. Suppose only 8 customers were included in each sample. Revise your interval and discuss the differences.
c. For part b, what population assumptions did you make?