1) Assume a normal distribution with known population variance. Calculate the LCL and USL for each of the following:

\f7.13 A personnel manager has found that historically the scores on aptitude tests given to applicants for entry- level positions follow a normal distribution with a standard deviation of 32.4 points. A random sample of nine test scores from the current group of applicants had a mean score of 187.9 points. a. Find an 80% confidence interval for the population mean score of the current group of applicants. b. Based on these sample results, a statistician found for the population mean a confidence interval ex- tending from 165.8 to 210.0 points. Find the confi- dence level of this interval