Is rap music more popular among young blacks

§ Is rap music more popular among young blacks than among young whites? A sample survey compared 634 randomly chosen blacks aged 15 to 25 with 567 randomly selected whites in the same age group. It found that 368 of the blacks and 130 of the whites listened to rap music every day. Construct a 98% confidence interval to estimate the difference between the proportions of black and white young people who listen to rap every day. § B) Show evidence that Normal Conditions have been satisfied. § Number of successes and failures in the two groups are 368, 266, 130, and 437, all of which are at least 10, it is safe to do Normal calculations

§ Is rap music more popular among young blacks than among young whites? A sample survey compared 634 randomly chosen blacks aged 15 to 25 with 567 randomly selected whites in the same age group. It found that 368 of the blacks and 130 of the whites listened to rap music every day. Construct a 98% confidence interval to estimate the difference between the proportions of black and white young people who listen to rap every day. § C) Construct the 98% confidence interval. § (0. 2898, 0. 4125)

§ Is rap music more popular among young blacks than among young whites? A sample survey compared 634 randomly chosen blacks aged 15 to 25 with 567 randomly selected whites in the same age group. It found that 368 of the blacks and 130 of the whites listened to rap music every day. Construct a 98% confidence interval to estimate the difference between the proportions of black and white young people who listen to rap every day. § D) Interpret the confidence interval. § We are 98% confident that the interval from 0. 2898 to 0. 4125 captures the true difference between the proportions of black and white young people who listen to rap every day

§ A study of the impact of caffeine consumption on reaction time was designed to correct for the impact of subjects’ prior sleep deprivation by dividing the 24 subjects into 12 pairs on the basis of the average hours of sleep they had for the previous 5 nights That is, the two with the highest average sleep were a pair, then the two with the next highest average sleep, etc. One randomly selected member of each pair was allowed to drink two cups of caffeinated coffee, and the other drank two cups of decaf. Each subject’s performance on a standard reaction-time test was recorded. Which of the following is the correct check of the “Normal/Large Sample” condition for this significance test? § a. Confirm (graphically) that the scores of the caffeine drinkers and the scores of the decaf drinks in the study could have come from Normal distributions. § b. Confirm (graphically) that the scores of the caffeine drinkers and the scores of the decaf drinks in the study, and the differences in scores within each pair of subjects could have come from Normal distributions. § c. Confirm that the differences in scores within each pair of subjects could have come from a Normal distribution. § d. Confirm that at least one of the sets of individual scores (from the caffeine or decaf group) and the differences in scores within each pair could have come from Normal distributions. § e. Because the central limit theorem applies to this situation, it is not necessary to check any of the samples for Normality.

§ What is the appropriate number of degrees of freedom to use when conducting a two-sample t-test for the difference between two means? A. n – 1 where n is the number of different populations B. n – 1 where n is the larger of the two sample sizes C. n – 1 where n is the smaller of the two sample sizes D. n – 1 where n is the number total number of observations in both samples combined § E. n – 2 where n is the number total number of observations in both samples combined § §

a) I only b) III Only d) II and III Only e) I, II, and III c) I and II Only

a) c) d) e) b)

a) 0. 07 b) 0. 14 d) 0. 72 e) 0. 86 c) 0. 28