Can you share an elementary explanation of how to calculate using Excel please? A hint is listed below. Thank you!

The operations manager at a compact fluorescent light bulb (CFL) factory needs to estimate the mean life of a large shipment of CFLs. The manufacturer's specifications are that the population standard deviation is 1,000 hours. A random sample of 64 CFLs indicated a sample mean life of 7,500 hours.

A)Construct a 95% confidence interval estimate for the population mean life of compact fluorescent light bulbs in this shipment.

B)Do you think that the manufacturer has the right to state that the compact fluorescent lightbulbs have a mean life of 8,000 hours, Explain?

C)Must you assume that the population compact fluorescent light bulb life is normally distributed? Explain?

D)Suppose that the standard deviation changes to 800 hours. What are your answers for (A) & (B)?

(Hint: for this problem for 95% confidence interval, you are finding the cumulative 2.5% and 97.5% points of the x bar that sandwiched the center 95%. you will use the observed X_bar as the mu and standard deviation / sqrt(n) as the sigma, and the same inverse normal cumulative function. Notice so far we have avoided using Z table lookup from the back of the book completely, but use excel function for all the calculation.)