Find the confidence interval estimate of the following problems on estimation of parameters. Then verify your answer using excel.

1. An independent researcher wishes to estimate the average amount of money a young professional spends in clothing each month. A sample of 30 young professional who spend in clothing found the mean to be Php 500 and the standard deviation to be Php 60. Find 95% confidence interval of the population mean.

2. The following are the IQ test scores of 31 randomly selected business students in a certain university.

113991048910291114114103105 106

1081301201311101271181198773

111103741121071039896112113

Estimate the mean IQ score for all business students using the following:

a. 99% confidence interval

b.95% confidence interval