答案和详解如下： Q4. In the estimated regression equation Y = 0.78 - 1.5 X, which of the following is least accurate when interpreting the slope coefficient? A) The dependent variable increases by 1.5 units if X decreases by 1 unit. B) The dependent variable declines by -1.5 units if X increases by 1 unit. C) If the value of X is zero, the value of Y will be -1.5. Correct answer is C) The slope represents the change in the dependent variable for a one-unit change in the independent variable. If the value of X is zero, the value of Y will be equal to the intercept, in this case, 0.78. Q5. Paul Frank is an analyst for the retail industry. He is examining the role of television viewing by teenagers on the sales of accessory stores. He gathered data and estimated the following regression of sales (in millions of dollars) on the number of hours watched by teenagers (in hours per week): Salest = 1.05 + 1.6 TVt
Which of the following is the most accurate interpretation of the estimated results? If TV watching: A) goes up by one hour per week, sales of accessories increase by $1.60. B) changes, no change in sales is expected. C) goes up by one hour per week, sales of accessories increase by $1.6 million. Correct answer is C) The interpretation of the slope coefficient is the change in the dependent variable (sales in millions of dollars) for a given one-unit change in the independent variable (TV hours per week). The intercept of 1.05 means that 1.05 million dollars worth of accessories is expected to be sold even if TV watching is zero. Q6. Sera Smith, a research analyst, had a hunch that there was a relationship between the percentage change in a firm’s number of salespeople and the percentage change in the firm’s sales during the following period. Smith ran a regression analysis on a sample of 50 firms, which resulted in a slope of 0.72, an intercept of +0.01, and an R2 value of 0.65. Based on this analysis, if a firm made no changes in the number of sales people, what percentage change in the firm’s sales during the following period does the regression model predict? A) +0.72%. B) +1.00%. C) +0.65%. Correct answer is B) The slope of the regression represents the linear relationship between the independent variable (the percent change in sales people) and the dependent variable, while the intercept represents the predicted value of the dependent variable if the independent variable is equal to zero. In this case, the percentage change in sales is equal to: 0.72(0) + 0.01 = +0.01. | 
发表于 2009-1-5 10:26
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