The admission office wants to estimate the mean age of allstudents enrolled at ZU. The estimate must be within half year ofthe population mean. Assume the population of ages is normallydistributed.  Also assume that the population standarddeviation is 1.4 years.
1- Determine the minimum sample size required to construct a 90%confidence interval for the population mean ?....
2-Repeat part (a) using a 99% confidence interval ? .....
  3-Which level of confidence requires a larger samplesize? Explain ....
