Interpret the confidence intervals for the differences described below. list K (a) Students' scores on an assessment were recorded before and after a reading program. To determine whether the program affected scores, a confidence interval is constructed for Ha, where d = post score - pre score. The confidence interval is (2.1, 4.8). O A. We are confident that scores are higher after the program than before the program on average. 12 O B. We are not confident of a change in scores. O C. We are confident that scores are lower after the program than before the program on average. In 3 (b) In an experiment to compare a new blood pressure drug to a placebo, researchers construct a confidence interval for 1 - H2, where u, = average heart rate for the drug group and H2 = average heart rate for the placebo group. The confidence interval is ( - 3.3, 1.0). O A. We are confident that the drug lowered blood pressure compared to a placebo. on 4 O B. We are confident that the drug raised blood pressure compared to a placebo. O C. We are not confident of a difference between the drug and a placebo. (c) To compare car ownership in the US to car ownership in France, researchers construct a confidence interval for 1 - P2, where p1 = the proportion of adults in the US who own a car and p2 = the proportion of adults in France who own a car. The confidence interval is (0.105, 0.118). O A. We are not confident of a difference in car ownership O B. We are confident that car ownership is lower in the US than in France. O C. We are confident that car ownership is higher in the US than in France