38. A game of chance is played in which the number of points scored in each game, has the X, distribution shown above. Which of the following is true for the sampling distribution of the sum, of Y, the scores when the game is played twice? (A) takes on values 0, 1, 2 with respective probabilities 0.3, 0.4, and 0.3. Y (B) takes on values 0, 2, 4 according to a binomial distribution with mean equal to 2. Y (C) on values 0, 2, 4 with respective probabilities 0.3, 0.4, and 0.3. Y (D) takes on values 0, 1, 2, 3, 4 according to a binomial distribution with mean equal to 2. Y (E) takes on values 0, 1, 2, 3, 4 with respective probabilities 0.09, 0.24, 0.34, 0.24, and 0.09. Y 39. A polling organization asks a random sample of 1,000 registered voters which of two candidates they plan to vote for in an upcoming election. Candidate A is preferred by 400 respondents, Candidate B is preferred by 500 respondents, and 100 respondents are undecided. George uses a large sample confidence interval for two proportions to estimate the difference in the population proportions favoring the two candidates. This procedure is not appropriate because (A) the two sample proportions were not computed from independent samples (B) the sample size was too small (C) the third category, undecided, makes the procedure invalid (D) the sample proportions are different; therefore the variances are probably different as well (E) George should have taken the difference and then used a large sample confidence interval for a single proportion instead 40. Two variables, and were measured for a random sample of 25 subjects, and two separate x y, regression models were fit to the data. Least squares estimation of the parameters in Model yielded A the following equation and residual plot.
38. A game of chance is played in which X, the number of points scored in each game, has the distribution shown above. Which of the following is true for the sampling distribution of the sum, Y, of the scores when the game is played twice? (A) Y takes on values 0, 1, 2 with respective probabilities 0.3, 0.4, and 0.3. (B) Y takes on values 0, 2, 4 according to a binomial distribution with mean equal to 2. (C) Y on values 0, 2, 4 with respective probabilities 0.3, 0.4, and 0.3. (D) Y takes on values 0, 1, 2, 3, 4 according to a binomial distribution with mean equal to 2. (E) Y takes on values 0, 1, 2, 3, 4 with respective probabilities 0.09, 0.24, 0.34, 0.24, and 0.09. 39. A polling organization asks a random sample of 1,000 registered voters which of two candidates they plan to vote for in an upcoming election. Candidate A is preferred by 400 respondents, Candidate B is preferred by 500 respondents, and 100 respondents are undecided. George uses a large sample confidence interval for two proportions to estimate the difference in the population proportions favoring the two candidates. This procedure is not appropriate because (A) the two sample proportions were not computed from independent samples (B) the sample size was too small (C) the third category, undecided, makes the procedure invalid (D) the sample proportions are different; therefore the variances are probably different as well (E) George should have taken the difference and then used a large sample confidence interval for a single proportion instead 40. Two variables, x and y, were measured for a random sample of 25 subjects, and two separate regression models were fit to the data. Least squares estimation of the parameters in Model A yielded the following equation and residual plot.
2007_ap_statistics_multiple_choice_exam.docx