Epidemiologists nd an association between high levels of cholesterol in the blood and heart disease. They conclude that cholesterol causes heart disease. However, a statistician argues that smoking confounds the association, meaning that ---- 0 None of the above. 0 Smoking causes heart disease, and smokers have high levels of cholesterol in their blood. 0 Smokers tend to eat a less healthful diet than non-smokers. Thus, smokers have high levels of cholesterol in the blood, which in turn causes heart disease. 0 The percentage of smokers is about the same among persons with high or low levels of cholesterol in the blood. 0 Smoking causes heart disease. Area under a histogram for data represen V [33301] percentage of some results in all data _ _ . chances for some result to happen in a chance process Area undera probability histogram repres Question 3 10 pts Suppose a hundred draws made at random with replacement from a box of numbered tickets. Determine each of the following statements isTrue or False. I. If the distribution of tickets in the box is extremely lopsided, the probability histogram for the sum of a moderate number of draws is probably also lopsided. II. The expected value forthe sum of draws is 100 times the expected value for the average of draws. Ill. The standard errorforthe sum of draws is 100 times the standard error for the average of draws. IV. The probability histogram for the sum of draws and the probability histogram for the average of the draws look exactly the same in standard units. V. If we repeat the process of taking the sum of draws from this box at random with replacement a hundred times, the histogram for the result will look exactly the same as the probability histogram. J [Choose] False True Determine each of the following statements about sampling methods isTrue or False. I. To decide whether a sample taken is representative or not, we only need to look at the sample itself to see if it has the same composition as the population. ll. Quota sampling is a probability sampling method. Ill. Simple Iandom sampling is an ideal sampling method because it eliminates all biases. IV. Simple random sampling is the same as drawing tickets at random with replacement from a box where every individual in population is represented as a ticket. V. In reality, even probability sampling methods can have bias. 5 pts Question 5 A study of the IQs of husbands and wives obtained the following results: Average IQ SD Husbands 100 Wives 100 Correlation coefficients r = 0.6. Which of the following is a sketch of the scatter diagram for this data? 150 100 Wife 50 50 100 150 Husband o 150 100 Wife 50 50 100 150 Husband O 130 100 Wife 50 50 100 150 Husband O 150 100 O Wife 50 50 100 150 Husband O None of the above .Question 6 10 pts Suppose a scattered diagram is for a pair of data (x,y) is plotted, and the scales for the horizontal and vertical scales are chosen such that 1 unit on horizontal scale = 1 SD for x-values 1 unit on vertical scale = 1 SD for y-values Decide each of the following statements is true or false. 1. The slope for the SD line is either 1 or -1. Il. The SD line and the regression line for y on x intersects at the point of average. Ill. The SD line is a smoothed version of the graph of averages. V. The regression line for y on x can be vertical. V. The stronger the correlation between x and y is, the closer the SD line and the regression lines are. */ [ Choose ] True False I Choose 1 V I Choose | V [ Choose Question 7 5 pts Three cards will be dealt from a well-shuffled deck. What is the chance of getting an ace or a king among the 3 cards? (A deck has 52 cards, of which 4 are aces and 4 are kings.) 32 37 . 30 O1 - (# #.") 0# X 3 Question 8 5 pts A survey research company uses random digit dialing. They have a contract, to estimate the percentage of people watching Spanish-language television in several Southwestern cities. They took a sample of size 1,000 in Austin, Texas-which has about 600,000 residents. They are satisfied with the accuracy of the estimates for Austin. Dallas has about twice the population of Austin, but similar demographics. To get about the same accuracy in Dallas as in Austin, what should the sample size the company take from Dallas, assuming that they would use exactly the same sampling process? O Need more information. O 2,00 1,000 0 500 O 4,000Question 9 6 pts Twenty-five draws are made at random with replacement from the box of 4 tickets: "1: "1", "2", "4". Matching the following graphs with descriptions. / [ Choose ] The probability histogram for the average of 20 draws The histogram for the numbers in the 20 draws The histogram for the numbers in the box I Choose V Question 10 14 pts Five hundred draws are made at random with replacement from a box with 10,000 tickets. The average of the box is un e draws was 71.3, and their SD was about 2.3. Decide each of the following statement is true or false. 1. The average of the box is likely to be around 71.3, and the SD of the box is likely to be around 2.3 1. The SE computed by 7506 8 0.1 says that this number 2.3 is likely to be off by 0.1 or so. 1. The SE computed by 7506 0.1 says that this number 71.3 is likely to be off by 0.1 or s IV. A 68%-confidence interval is for the average of box is /1.3 0. 5 VI. About 68% of tickets in the box are within the range of 71.3 + 0.1. VII. About 68% of tickets in the box are within the range of 71.3 + 2.3. [ Choose ] I Choose | I Choose | I Choose |