Question # 1: Total plasma volume is important in determining the required plasma component in blood replacement therapy for a person undergoing surgery. Plasma volume is influenced by the overall health and physical activity of an individual. Suppose that a random sample of46male firefighters are tested and that they have a plasma volume sample mean ofx= 37.5 ml/kg(milliliters plasma per kilogram body weight). Assume that=7.90ml/kgfor the distribution of blood plasma.

(a) Find a 99% confidence interval for the population mean blood plasma volume in male firefighters. What is the margin of error? (Round your answers to two decimal places.)

lower limit___________

upper limit______

margin of error_________

(b) What conditions are necessary for your calculations? (Select all that apply.)

is known

is unknown

nis large

the distribution of weights is uniform

the distribution of weights is normal

(c) Interpret your results in the context of this problem.

The probability that this interval contains the true average blood plasma volume in male firefighters is 0.01.

99% of the intervals created using this method will contain the true average blood plasma volume in male firefighters.

The probability that this interval contains the true average blood plasma volume in male firefighters is 0.99.

1% of the intervals created using this method will contain the true average blood plasma volume in male firefighters.

(d) Find the sample size necessary for a 99% confidence level with maximal margin of errorE=2.60for the mean plasma volume in male firefighters. (Round up to the nearest whole number.)

______ male firefighters

Question # 2

Jobs and productivity! How do banks rate? One way to answer this question is to examine annual profits per employee. The following is data about annual profits per employee (in units of1 thousanddollars per employee) for representative companies in financial services. Assume9.5thousanddollars.

57.230.628.529.942.534.855.158.642.533.033.636.927.047.133.828.128.529.136.536.126.927.828.829.331.531.731.138.032.031.732.923.154.943.836.931.925.523.229.822.326.526.7

(a) Use a calculator or appropriate computer software to findxfor the preceding data. (Round your answer to two decimal places.)

_____________ thousand dollars

(b) Let us say that the preceding data are representative of the entire sector of (successful) financial services corporations. Find a75% confidenceinterval for, the average annual profit per employee for all successful banks. (Round your answers to two decimal places.)

lower limit__________thousand dollars

upper limit_____________thousand dollars

(c) (e) Find a 90% confidence interval for, the average annual profit per employee for all successful banks. (Round your answers to two decimal places.)

lower limit___________thousand dollars

upper limit________________thousand dollars