A manufacturing company's quality control personnel have recorded the proportion of defective items for each of 500 monthly shipments of one of the computer components that the company produces. The data are in the file P08_04.xlsx. The quality control department manager does not have sufficient time to review all of these data. Rather, she would like to examine the proportions of defective items for a sample of these shipments.

Round your answers to three decimal places, if necessary.

a. Generate a simple random sample of size 25.

Sample Mean?

Sample Standard Deviation?

b. Using the sample generated in part a, calculate a 95% confidence interval for the mean proportion of defective items over all monthly shipments. Assume that the population consists of the proportion of defective items for each of the given 500 monthly shipments.

Lower Limit

Upper Limit

c. Interpret the 95% confidence interval constructed in part b.

We are ..... % confident that the proportion of defective items in the........ monthly shipments is within or Outside? the lower and upper limits.

d. Does the 95% confidence interval contain the actual population mean in this case?

Yes/No?

What proportion of many similarly constructed confidence intervals should include the true population mean?