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Unformatted text preview: Stats for Strategy Fall 2008 HOMEWORK 10 (covers Topic 11 and Topic 12, Part 1. Due Monday, Dec. 1) DIRECTIONS: Part of this assignment requires reading in the supplementary textbook Chapter 17: Logistic Regression. Find this chapter as a PDF file on the main course webpage. Some of the exercises listed below include special instructions which modify or clarify textbook instructions. Data sets for some exercises are available on the Data Sets link from the course website. (Remember to open data files as worksheets in MINITAB .) Homework Part 1: Topic 11 (Logistic Regression) A. Mail-Order Sales Open the PDF file for the supplementary textbook Chapter 17: Logistic Regression on the main course webpage. Read the description of mail-order sales on the first page. Answer these questions: (a) There are 5 predictor variables and a response variable described for this logistic regression. Lets call them x 1 , x 2 , x 3 , x 4 , x 5 , and y . Write an English definition for all 6 variables, including the meaning of 0 and 1 for binary variables. (b) Which of the variables are binary ? Which are quantitative (i.e., numerical )? B. College Student Drinking The textbook introduces logistic regression with the same data on drinking as used in Example 2 of the Topic 11 notes. Quickly glance over the notes you wrote for Example 2 on pages 8-11 of the Topic 11 notes. Now open page 17-2 of the textbook Chapter 17 PDF file. Read pages 17-2 and 17-3 at a leisurely pace. Soak up what the textbook says and occasionally glance at the Topic 11 notes to confirm that the books answers are the same as ours. Next read Model for logistic regression at the bottom of page 17-4 and all of page 17-5. Then read Fitting and interpreting the logistic regression model on pages 17-6 and 17-7. Pay particular attention to the way the book calculates b and b 1 at the top of 17-7. Are these the same estimates (except for rounding) that MINITAB logistic regression produces in the output shown on page 9 of the Topic 11 notes? Lastly, read Section 17.1 Summary at the bottom of page 17-4 and top of page 17-5. Open MINITAB and type the drinking data into the worksheet: C1 C2 C3 C4 Gender Binge Total Men 1 1630 7180 Women 1684 9916 1 Reproduce the MINITAB output shown on page 9 of the Topic 11 notes. (Recall that in class we made some corrections to the Minitab instructions shown in the notes.) Here are the correct MINITAB steps: Stat > Regression > Binary Logistic Regression > (Click radio button Response in event/trial format) > (Enter Binge for Number of events, Total for Number of trials) > (Select all predictor variables for the Model : Gender ) > (Select all binary predictor variable as Factors : Gender ) > OK Notice that theres some extra output at the bottom which you can ignore....
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This note was uploaded on 02/03/2012 for the course 06E 071 taught by Professor Stuff during the Spring '11 term at University of Iowa.
- Spring '11