Repeat exercise 1 using a 95% confidence interval for a different random sample: employee numbers 4, 47, 45, 12, and 69. Also, answer the following:
a. Find the average, standard deviation, and standard error for annual salary based on this sample.
b. Find the 95% confidence interval for the population mean salary.
c. Draw a graph in the style of Figure 9.1.5 indicating the sample average and confidence interval.
d. In real life, what (if anything) could you do about the fact that the population mean is not in the confidence interval?
e. Also compute 99% and 99.9% intervals. At what confidence level (if any) is the confidence interval large enough to include the population mean?