4-10 The operations manager of a musical instrument distributor feels that demand for a particular type of guitar may be related to the number of YouTube views for a music video by the popular rock group Marble Pumpkins during the preceding month. The manager has collected the data shown in the following table:Graph these data to see whether a linear equation might describe the relationship between the views on YouTube and guitar sales.Using the equations presented in this chapter, compute the SST, SSE, and SSR. Find the least-squares regression line for these data.Using the regression equation, predict guitar sales if there were 40,000 views last month.
4-12 Using computer software, find the least-squares regression line for the data in Problem 4-10. Based on the F test, is there a statistically significant relationship between the demand for guitars and the number of YouTube views?
4-26 A sample of 20 automobiles was taken, and the miles per gallon (MPG), horsepower, and total weight were recorded. Develop a linear regression model to predict MPG, using horsepower as the only independent variable. Develop another model with weight as the independent variable. Which of these two models is better? Explain.
5-21 A college student has just completed her junior year. The following table summarizes her grade-point average (GPA) for each of the past nine quarters:Forecast the student’s GPA for the fall semester of her senior year by using a three-period moving average.Forecast the student’s GPA for the fall semester of her senior year by using exponential smoothing with .Which of the two methods provides a more accurate forecast? Justify your answer.
