1) 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.

2. A study of a company's practice regarding the payment of invoices revealed that an invoice was paid an average of 20 days after it was received. The standard deviation equaled five days. Assuming that the distribution is normal, what percent of the invoices were paid within 15 days of receipt?

3. A national manufacturer of unattached garages discovered that the distribution of the lengths of time it takes two construction workers to erect the Red Barn model is approximately normally distributed with a mean of 32 hours and a standard deviation of 2 hours. What percent of the garages take between 30 and 34 hours to erect?

Solution Preview

1.

A) Estimate of population mean = sample mean according to central limit theorem. Hence answer is 3.01

B) 95% confidence interval for mean

According to central limit theorem, the sample mean is normally distributed with mean = population mean and standard
deviation = sample sd/sqrt(n) = 0.03/sqrt(36) = 0.03/6 = 0.005

z ...

Solution Summary

The solution examines estimating the population mean and determining the normal distribution. The percent of invoices paid on time is determined.

... treatment of the drug; develop a point estimate of the ... a sample mean SAT score within 10 of the population mean? 3) Show the sampling distribution of p 4) find ...

...mean SAT score within 20 of the population mean? ... Appliance magazines provided estimates of the life expectancy of ... A. Develop a point estimate of the population...

... chain is interested in estimating the average ... sample standard deviation to estimate the population... n > 15 For normal population distributions, the sampling ...

... department store chain is interested in estimating the average ... closer to 0.50 that p is estimated to be ... given 14 A statistician wishes to estimate the average ...

... Interval Construct/Estimate a Population Mean/Estimate the Value of a ... b) No prior estimates are used? ... Data Estimate of True Proportion 0.5 Sampling Error 0.025 ...

... and draw a dotplot for sampling distribution of the ... that the sample mean will equal the population mean. ... the sampling error made in estimating the population...

... 2. A phone company wants to estimate the mean duration ... Find the margin of error in estimating μ at ... of size 49 are selected randomly from the population. ...

... normal distribution; (2) how to use Excel to select a simple random sample; (3) how to use Excel built-in functions and procedures to estimate population mean...

... taking a random sample of 18 items in an effort to estimate the population mean. ... Question 9: A researcher is interested in estimating the mean value for a ...