Q1 College Graduate-Level Wages. The Economic Policy Institute periodically issues reports on wages of entry-level workers. The institute reported that entry-level wages for male college graduates were $21.68 per hour and for female college graduates were $18.80 per hour in 2011. Assume that the standard deviation for male graduates is $2.30 and for female graduates it is $2.05.

a.What is the sampling distribution of for a random sample of 50 male college graduates?

b.What is the sampling distribution of for a random sample of 50 female college graduates?

c.In which of the preceding two cases, part (a) or part (b), is the standard error of smaller? Why?

Q2 Years to Bond Maturity. A sample containing years to maturity and yield for 40 corporate bonds is contained in the file CorporateBonds. (data is on q2 sheet)

a.What is the sample mean years to maturity for corporate bonds and what is the sample standard deviation?

b. Develop a 95% confidence interval for the population mean years to maturity.

c. What is the sample mean yield on corporate bonds and what is the sample standard deviation?

d. Develop a 95% confidence interval for the population mean yield on corporate bonds.

Q3 Automobile Insurance Premiums. The average annual premium for automobile insurance in the United States is $1,503. The following annual premiums ($) are representative of the web site's findings for the state of Michigan. (data is on q3 sheet)

Assume the population is approximately normal.

a. Provide a point estimate of the mean annual automobile insurance premium in Michigan.

b. Develop a 95% confidence interval for the mean annual automobile insurance premium in Michigan.

c. Does the 95% confidence interval for the annual automobile insurance premium in Michigan include the national average for the United States? What is your interpretation of the relationship between auto insurance premiums in Michigan and the national average?

Q4 Production Rate and Quality Control. In a manufacturing process the assembly line speed (feet per minute) was thought to affect the number of defective parts found during the inspection process. To test this theory, managers devised a situation in which the same batch of parts was inspected visually at a variety of line speeds. They collected the following data: (data is on q4sheet) Line Speed (ft/min) No. of Defective Parts Found 20 21 20 19 40 15 30 16 60 14 40 17 a. Develop a scatter chart with line speed as the independent variable. What does the scatter chart indicate about the relationship between line speed and the number of defective parts found? b. Use the data to develop an estimated regression equation that could be used to predict the number of defective parts found, given the line speed. What is the estimated regression model? c. Test whether each of the regression parameters and is equal to zero at a 0.01 level of significance. What are the correct interpretations of the estimated regression parameters? Are these interpretations reasonable? d. How much of the variation in the number of defective parts found for the sample data does the model you estimated in part (b) explain?

Q5 Bus Maintenance. The regional transit authority for a major metropolitan area wants to determine whether there is a relationship between the age of a bus and the annual maintenance cost. A sample of 10 buses resulted in the following data: (data is on q5 sheet) Age of Bus (years) Annual Maintenance Cost ($) 1 350 2 370 2 480 2 520 2 590 3 550 4 750 4 800 5 790 5 950 a. Develop a scatter chart for these data. What does the scatter chart indicate about the relationship between age of a bus and the annual maintenance cost?

b. Use the data to develop an estimated regression equation that could be used to predict the annual maintenance cost given the age of the bus. What is the estimated regression model?

b. Test whether each of the regression parameters and is equal to zero at a 0.05 level of significance. What are the correct interpretations of the estimated regression parameters? Are these interpretations reasonable?

c. How much of the variation in the sample values of annual maintenance cost does the model you estimated in part (b) explain?

d. What do you predict the annual maintenance cost to be for a 3.5-year-old bus?

Q6 Forecasting Monthly Data. Consider the following time series data: Month 1 2 3 4 5 6 7 Value 24 13 20 12 19 23 15 a. Construct a time series plot. What type of pattern exists in the data? b. Develop a three-week moving average for this time series. Compute MSE and a forecast for week c. Use compute the exponential smoothing values for the time series. Compute MSE and a forecast for week 8. d. Compare the three-week moving average forecast with the exponential smoothing forecast using Which appears to provide the better forecast based on MSE? e. Use trial and error to find a value of the exponential smoothing coefficient that results in a smaller MSE than what you calculated for .

Q7 University Enrollment. Because of high tuition costs at state and private universities, enrollments at community colleges have increased dramatically in recent years. The following data show the enrollment for Jefferson Community College for the nine most recent years: (data is on q7 sheet) Year Period (t) Enrollment (1,000s) 2001 1 6.5 2002 2 8.1 2003 3 8.4 2004 4 10.2 2005 5 12.5 2006 6 13.3 2007 7 13.7 2008 8 17.2 2009 9 18.1 a. Construct a time series plot. What type of pattern exists in the data? b. Use simple linear regression analysis to find the parameters for the line that minimizes MSE for this time series. c. What is the forecast for year 10?

Everything should be answered in an excel file