Question: Cost observations provided for 21 production situations have an average of $149.67 and a standard deviation of $38.85.
a. Find and interpret the two-sided 95% confidence interval.
b. Find the two-sided 99.9% confidence interval.
c. Find the one-sided 95% confidence interval that claims that the population mean for this cost is at least some amount.
d. Find the one-sided 99% confidence interval that claims that the population mean for this cost is no larger than some amount.