A Random Sample of 100,000 Credit Sales in a Department

Multiple Choice

A random sample of 100,000 credit sales in a department store showed an average sale of $87.25. From past data, it is known that the standard deviation of the population is $20.00. What is the 95% confidence interval of the population mean?

A) $87.22 to $87.28
B) $87.13 to $87.37
C) $19.97 to $20.03
D) $19.88 to $20.12