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Unformatted text preview: Stat 350 W08 Exam 2 Solutions p a g e 1 1. a. That the variances for battery life for the two populations are equal Or Equal population variances OR Or Equal population standard deviations is fine too! 2 2 2 1 = b. Test statistic = 2.55 pvalue = 0.029 Decision: Reject H o Conclusion: There (circle one) is sufficient evidence to say that the average battery life of all generic batteries differs from the average battery life of all brand name batteries. c. Researcher Fred wants to test the same hypotheses as Jeff but at the 1% level What pvalue would Fred use to test his hypothesis? Freds pvalue is still 0.029 d. Researcher Suzies theory was that brand name batteries would be better (last longer) than generic batteries, so her hypotheses are H o : 1 2 = 0 versus H a : 1 2 < 0. Her significance level is 5%. What pvalue would Suzie use to test her hypothesis? Suzies pvalue will be 1 (0.029/2) = 0.9855 e. Who will come to the same conclusion as Jeff? Circle one: Neither Fred nor Suzie 2. a. This paired design study is (circle one): an observational study an experiment . b. What is the observed value of the test statistic? ____ t = 3.150/0.958 = 3.29 ______ c. If there really is no difference in the aggression scores on average, what is the distribution of the test statistic? (be specific i.e. include numbers) t distribution with 19 df OR t(19) d. If there really is no difference in the aggression scores on average, what is the expected value of the...
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This note was uploaded on 04/02/2008 for the course STAT 350 taught by Professor Gunderson during the Winter '08 term at University of Michigan.
 Winter '08
 Gunderson
 Standard Deviation, Variance

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