In a random sample of Toyota car owners, 83 out of 112 said they were satisfied with the Toyota front-wheel drive, while in a similar survey of Subaru owners, 76 out of 81 said they were satisfied with the Subaru four-wheel drive. A 90% confidence interval estimate for the difference in proportions between Toyota and Subaru car owners who are satisfied with their drive systems is reported to be -0.197 ± 0.081. Which is a proper conclusion?
(A)The interval is invalid because probabilities cannot be negative. (B)The interval is invalid because it does not contain zero. (C)Subaru owners are approximately 19.7% more satisfied with their drive systems than are Toyota owners. (D)We are 90% confident that the difference in proportions between Toyota and Subaru car owners who are satisfied with their drive systems is between -0.278 and -0.116.
D