BUS352 Chapter 12 Problems
12.3
| 12.3 Fitting a straight line to a set of data yields the following |
| prediction line: |
| Yn i = 16 - 0.5Xi |
| a. Interpret the meaning of the Y intercept, b0. |
| b. Interpret the meaning of the slope, b1. |
| c. Predict the value of Y for X = 6. |
12.7
| 12.7 Starbucks Coffee Co. uses a data-based approach to improving |
| the quality and customer satisfaction of its products. |
| When survey data indicated that Starbucks needed to improve its |
| package-sealing process, an experiment was conducted to determine |
| the factors in the bag-sealing equipment that might be affecting |
| the ease of opening the bag without tearing the inner liner |
| of the bag. (Data extracted from L. Johnson and S. Burrows, “For |
| Starbucks, It’s in the Bag,” Quality Progress, March 2011, |
| pp. 17–23.) One factor that could affect the rating of the ability of |
| the bag to resist tears was the plate gap on the bag-sealing equipment. |
| Data were collected on 19 bags in which the plate gap was |
| varied. The results are stored in Starbucks . |
| a. Construct a scatter plot. |
| b. Assuming a linear relationship, use the least-squares method to |
| determine the regression coefficients b0 and b1. |
| c. Interpret the meaning of the slope, b1, in this problem. |
| d. Predict the mean tear rating when the plate gap is equal to 0. |
| e. What should you tell management of Starbucks about the relationship |
| between the plate gap and the tear rating? |
12.9
| 12.9 An agent for a residential real estate company in a suburb |
| located outside of Washington, DC, has the business objective |
| of developing more accurate estimates of the monthly rental |
| cost for apartments. Toward that goal, the agent would like to |
| use the size of an apartment, as defined by square footage to |
| predict the monthly rental cost. The agent selects a sample of |
| 48 one-bedroom apartments and collects and stores the data in |
| RentSilverSpring . |
| a. Construct a scatter plot. |
| b. Use the least-squares method to determine the regression coefficients |
| b0 and b1. |
| c. Interpret the meaning of b0 and b1 in this problem. |
| d. Predict the mean monthly rent for an apartment that has 800 |
| square feet. |
| e. Why would it not be appropriate to use the model to predict the |
| monthly rent for apartments that have 1,500 square feet? |
| f. Your friends Jim and Jennifer are considering signing a lease |
| for a one-bedroom apartment in this residential neighborhood. |
| They are trying to decide between two apartments, one with |
| 800 square feet for a monthly rent of $1,130 and the other |
| with 830 square feet for a monthly rent of $1,410. Based on |
| (a) through (d), which apartment do you think is a better deal? |
12.19
| 12.19 In Problem 12.7 on page 424, you used the plate gap on |
| the bag-sealing equipment to predict the tear rating of a bag of coffee |
| (stored in Starbucks ). Using the results of that problem, |
| a. determine the coefficient of determination, r2, and interpret its |
| meaning. |
| b. determine the standard error of the estimate. |
| c. How useful do you think this regression model is for predicting the |
| tear rating based on the plate gap in the bag-sealing equipment? |
12.21
| 12.21 In Problem 12.9 on page 424, an agent for a real |
| estate company wanted to predict the monthly rent for onebedroom |
| apartments, based on the size of the apartment (stored |
| in Rent-SilverSpring ). Using the results of that problem, |
| a. determine the coefficient of determination, r2, and interpret its |
| meaning. |
| b. determine the standard error of the estimate. |
| c. How useful do you think this regression model is for predicting |
| the monthly rent? |
| d. Can you think of other variables that might explain the variation |
| in monthly rent? |