课程名称：统计学 课程性质：整开 课程范围：Chapter 14 - 16 开课教师：丁兆平 开课学院：商学院 开课系级：统计系 考试日期(年月日)：2014/5/29 考试时限(Mins)：60 min 附注： 试题本文： 1. The district manager of Jasons, a large discount electronic chain, is investing why certain stores in her region are performing better than others. She believes that three factors are related to total sales: the number of competitors in the region, the population in the surrounding area, and the amount spent on advertising. From her district, consisting of several hundred stores, she selects a random sample of 30 stores. For each store, she gathered the following information. Y = total sales last years (in $ thousands) X1= number of competitors in the region X2= population of the region (in millions) X3= advertising expense (in $ thousands) The sample data were run on Minitab, with the following results. Analysis of variance SOURCE DF SS MS Regression 3 3050.00 1016.67 Error 26 2200.00 84.62 Total 29 5250.00 Predictor Coef StDeV t-ration Constant 14.00 7.00 2.00 X1 -1.00 0.70 -1.43 X2 30.00 5.20 5.77 X3 0.20 0.08 2.50 a. What are the estimated sales for the Bryne store, which has four competitors, a regional population of 0.4 (400,000), and an advertising expense of 30 ($30,000)? (10 pts) b. Compute the R^2 value. (10 pts) c. Compute the multiple standard error of estimate. (5 pts) d. Conduct a global test of hypothesis to determine whether any of regression coefficients are not equal to zero. Use the 0.05 level of significance. (10 pts) e. Conduct tests of hypotheses to determine which of the independent variables have significant regression coefficients. Which variables would you consider eliminating? Use the 0.05 significance. (10 pts) 2. Betts Electronics purchases three replacement parts for robotic machines used in its manufacturing process. Information on the price of the replacement parts and the quantity purchased is given below. Price Quantity Part 2000 2009 2000 2009 RC-33 $0.50 $0.60 $320 $340 SM-14 1.20 0.90 110 130 WC-50 0.85 1.00 230 250 a. Compute Laspeyres' price index for 2009 using 2000 as the base period. (10 pts) b. Compute Paaschhe's index for 2009 using 2000 as the base period. (10 pts) c. Determine Fisher's ideal index using the value for the Laspeyres and Paasche indexes computed in the two previous problems. (10 pts) d. Determine a value index for 2009 using 2000 as the base period. (10 pts) 3. The sales, in billion of dollars, of Keller Overhead Door Inc. for 2005 to 2010 are: Year Sales 2005 7.45 2006 7.83 2007 8.07 2008 7.94 2009 7.76 2010 7.90 a. Determine the least squares trend equation.(10 pts) b. Estimate the net sales for 2013. (5 pts) ※ 编辑: Inosxz (111.253.63.184), 07/05/2014 14:52:17