1. The accounting department at Wosten Metarials a national manufacturer of unattacted garages reports that it takes two construction workers a mean of 32 hours and standard deviation of 2 hours to erect the Red Baorn Model. Assume the assembly times follow the normal distribution
  1. Detetmine the z values for 29 and 34 hours. What percent of the garages take between 32 hours and 34 hours to erect?

C.What percent of the garages take 28.7 hours or less to erect?

  1. A study of long distance phone calls made from the corporate offices of Pepsi Bottling Group, in Somers, New York, revealed the length of the calls, in minutes, follows the normal probability distribution. The mean length of time per call was 4.2 minutes and the standard deviation was 0.60 minutes
  1. What fraction of the calls last between 4.2 and 5 minutes?
  2. What fraction of the calls last more than 5 minutes?
  1. What fraction of the calls last between 4 and 6 minutes?
  1. The annual commissions earned by sales representatives of Machine Products, INC, a manufacturer of light machinery, follow the normal probability distribution. The mean yearly amount earned is $40,000 and standard deviation is $5, 000.
  1. What percent of the sales representatives earn more than $42, 000 per year?

C . What percent of the sales representatives earn between $32,000 and 35,000?

  1. At downtown office of the First National Bank there are five tellers. Last week the tellers made the following number of erors each: 2, 3, 5, 3, and 5.

A. How many different samples of 2 tellers are possible?
B. List all possible samples of size 2 and compute the mean of each

C. Compute the mean of the sample means and compare it to the population mean

  1. Information from the American Institute of insurance indicates the mean amount of life insruance per household in the United States is $110,000. This distribution follows the normal distribution with a standard deviation of $40,000.
  1. If we select a random sample of 50 households, what is the standard eror of the mean?
  2. What is the expected shape of the distribution of the sample mean?
  3. What is the likelihood of selecting a sample with a mean of at least $112,000?
  4. What is the likelihood of selecting sample with a mean of more than $100,000?
  5. Find the likelihood of selecting a sample with a mean of more than $100,000 but less than $112,000
  1. The mean amount purchased by a typical customer at Churchill’s Grocery Store is $23.50 with standard deviation of $5.00. Assume the distribution of amounts purchased follows the normal distribution. For a sample of 50 customers, answer the following question.
  1. What is likelihood the sample mean is at least $25.00?
  2. What is likelihood the sample mean is greater than $22.50 but less than $25.00?
  1. Ms. Maria Wilson is considering runing for mayor of the town of Bear Gluch, Montana. Before completing the petitions, she decided to conduct a survey of voters in Bear Gluch. A sample of 400 voters reveals that 300 would support her in the Nowember election.
  1. Estimate the value of the population proportion.
  2. Develop a 99 percent confidence interval for the population proportion.
  3. Interpret your findings.
  1. A state meat inspector in Iowa has been given the assignment ot estimating thr mean net weight of packages of ground chuck labeled “3 pounds” Of course, he realizes that the weights of cannot be precisely 3 pounds. A sample of 36 packages reveals the mean weights to be 3.01 pounds, with standard deviation of 0.03 pounds.
  1. What is the estimated population mean?
  2. Determine a 95 percent confidence interval for the population mean
  1. Human Relations Department of Electronic Inc, would like to include a dental plan as part of the benefits package. The question is: how much does typical employee and his or her family spend per year on dental expenses? A sample of 45 employees reveals the mean amount spent last year was $1,820, with a standard deviation of $660.
  1. Construct a 95 percent confidence interval for the population mean.
  2. The information from part (a) was given to president of Electronic, Inc. He indicated he could afford $1,700 of dental expenses per employee. Is it possible that the population mean could be $1,700? Justify your answer.

10 . An important factor in selling a residential property is the number of people who look through the home. A sample of 15 homes recently sold in Buffalo, New York, area revealed the mean number looking through each home was 24 and the standard deviation of the sample was 5 people. Develop a 98 percent confidence interval for the population mean.