8.82 Time spent on emails per week In a survey conducted in 2014, the General Social Survey (GSS) asked a sample of 7446 Americans how many minutes or hours they spent sending and answering emails. The results showed an average of 5.234 hours of email usage per week with a standard deviation of 9.543 hours.

a. Construct a 95% confidence interval for the population mean. Interpret.

b. What assumption about the population distribution of the number of hours spent per week on emails does the confidence interval method make?

c. If the population distribution is not normal, does this invalidate the results? Explain.