In a random sample of 26 computers, the mean repair cost was 143$ with a standard deviation of 35$.

A) Construct a 95% confidence interval for the population mean,u. Assume the population has a normal distribution. Critical value 2.060

B) Suppose you did some research on repair cost for computers and found that the standard deviation is 35. Use the normal distribution to construct a 95% confidence interval for the population mean ,u