Question

Exercise. A researcher wants to test:

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What’s wrong with this?

Exercise 7.24. Although the Environmental Protection Agency (EPA) establishes the tests to determine the fuel economy of new cars, it often does not perform them. Instead, the test protocols are given to the car companies, and the companies perform the tests themselves. To keep the industry honest, the EPA runs some spot checks each year. Recently, the EPA announced that Hyundai and Kia must lower their fuel economy estimates for many of their models. Here are some city miles per gallon values for one of the models the EPA investigated.

28.0	25.7	25.8	28.0	28.5	29.8	30.2	30.3
26.9	28.3	29.8	27.2	26.7	27.7	29.5	28.0

Give a 95% confidence interval for the mean city mpg for this model.

Exercise p. 602. A student decided to enroll in a reading course that allegedly increases reading speed and comprehension. Prior to enrolling in the class,  he read 198 words per minute. The following data represent the words per minute for 10 different passages read after the course.

206	217	197	199	210
210	197	212	227	209

Was the class effective? Use the 0.10 level of significance.

Exercise p. 528. In a clinical trial of Nasonex, 3774 adult and adolescent allergy patients were randomly divided into two groups. The patients in the experimental group received 200 µg of Nasonex, while the patients in the control group received a placebo. Of the 2103 patients in the experimental group, 547 reported headaches as a side effect. Of the 1671 patients in the control group, 368 reported  headaches as a side effect. Is there significant evidence to conclude that the proportion of Nasonex users who experienced headaches as a side effect is greater than the proportion in the control group at the .05 significance level?

Exercise p. 538. Professor Andy Neill measured the time (seconds) require to catch a falling meter stick for 12 randomly selected students’ dominant hand and nondominant hand. Professor Neill wants to know if the reaction time in an individual’s dominant hand is less than the reaction time in his or her nondominant hand. A coin flip is used to determine whether reaction time is measured using the dominant or nondominant hand first. Conduct the test at the .05 significance level.

Student	1	2	3	4	5	6	7	8	9	10	11	12
Dominant hand	.177	.210	.186	.189	.198	.194	.160	.163	.166	.152	.190	.172
Nondominant hand	.179	.202	.208	.184	.215	.193	.194	.160	.209	.164	.210	.197

Exercise. The heights of 2-year-old girls are normally distributed with a mean of 30 in and a standard deviation of 6 in. We want to test

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We will take a random sample of 40 girls and reject the null when the p-value is less than .05. The power of this test is .928. What does this mean?

Answer 1