Quiz 7: Hypothesis Testing in Statistics, Quizzes of Probability and Statistics

Download Quiz 7: Hypothesis Testing in Statistics and more Quizzes Probability and Statistics in PDF only on Docsity! Quiz 7 Name Math 243 GTF May 21, 2009 Disc. Time 1. On a certain 6th grade math test, it is suspected that females will score higher than males. A simple random sample of 21 6th graders, 11 male and 10 female, from around the country are given the math test. The scores are given below: Male 43 55 60 63 71 72 74 75 81 81 82 Female 58 59 59 71 72 72 73 84 85 96 Is there significant evidence at the α = 0.01 level that females perform better on the test than males? You may assume that the appropriate test is safe to use. Be sure to state your conclusion in language appropriate to the context of the problem. Do not just fill in the blanks; you will be graded on showing the appropriate work. Hypotheses: Let µ1 be the mean score of all 6th grade females. Let µ2 be the mean score of all 6th grade males. H0 : µ1 = µ2 Ha : µ1 > µ2 Test statistic: t ≈ 0.75078 P -value (or range of values for P ): P ≈ 0.23105 or 0.2 < P < 0.25 Conclusion: Since P > α there is not sufficient evidence to reject the null hypothesis. There is not good evidence that 6th grade females perform better than 6th grade males on this math test. 2. Mark wants to do a hypothesis test using the t procedure. He correctly chooses a sample of size 20 and collects the data shown in the stemplot below. Looking at the stem plot, which of the following BEST completes the sentence: Use of the t procedure is (a) appropriate since the sample size is large enough. (b) not appropriate since the sample size is only 20. (c) not appropriate because of the presence of outliers. (d) appropriate because there are no outliers. (e) not appropriate because the data have two peaks. (f) appropriate because the data are symmetric. (g) not appropriate because Mark doesn’t know the standard deviation of the population. (h) appropriate because the data are normal. 0 1 1 2 2 3 4 3 0 2 3 9 4 5 6 5 1 6 0 2 5 7 1 1 8 4 9 3 10 9 11 1