# Sampling error & Confidence Interval

21. What is sampling error? Could the value of the sampling error be zero? If it were zero, what would this mean?

22. List the reasons for sampling. Give an example of each reason for sampling.

32. A state meat inspector in Iowa has been given the assignment of estimating the mean net weight of packages of ground chuck labeled "3 pounds." Of course, he realizes that the weights cannot be precisely 3 pounds. A sample of 36 packages reveals the mean weight to be 3.01 pounds, with a standard deviation of 0.03 pounds.

a. What is the estimated population mean?

b. Determine a 95 percent confidence interval for the population mean.

46. As a condition of employment, Fashion Industries applicants must pass a drug test. Of the last 220 applicants 14 failed the test. Develop a 99 percent confidence interval for the proportion of applicants that fail the test. Would it be reasonable to conclude that more than 10 percent of the applicants are now failing the test? In addition to the test ing of applicants, Fashion Industries randomly tests its employees throughout the year. Last year in the 400 random tests conducted, 14 employees failed the test. Would it be reasonable to conclude that less than 5 percent of the employees are not able to pass the random drug test?

Please use excel.

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#### Solution Summary

The solution provides step by step method for the calculation of confidence interval for mean and population proportion. The solution also provides a detailed explanation on sampling error and list the reasons for sampling with examples. Formula for the calculation and Interpretations of the results are also included. The user can edit the inputs and obtain the complete results for a new set of data.