Final_Review_1_Solutions

Or do you oppose drilling for oil and natural gas o

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Unformatted text preview: at 1900 kcal. (g) The nutritionist would arrive at the same conclusion at α = 0.10. 7. In a survey conducted by Survey USA on July 12, 2010, 827 registered voters in California were asked “Do you support? Or do you oppose? drilling for oil and natural gas off the Coast of California? Or do you not know enough to say?” Below is the distribution of responses based on whether or not the respondent graduated from college. We might expect that college graduates would be more likely to have an opinion on this issue than non-college graduates. Therefore we are interested in finding out if the proportion of college graduates who do not have an opinion on the matter, i.e. responded do not know, is lower than the proportion of non-college graduates who do not have an opinion on the matter. Response Support Oppose Do not know Total College Yes 154 180 104 438 Grad No 132 126 131 389 i. What percent of the college graduates and what percent of the non-college graduates in this sample do not know enough to have an opinion on drilling for oil and natural gas off the Coast of California? 104 = 0.237 438 131 P (Do not know|N on College Grad) = = 0.337 389 P (Do not know|College Grad) = 4 ii. Which of the below is the appropriate set of hypotheses? (a) H0 : pcollege grad = pnon college grad ˆ ˆ HA : pcollege grad < pnon college grad ˆ ˆ (b) H0 : pcollege grad = pnon college grad HA : pcollege grad ￿= pnon college grad (c) H0 : pcollege grad = pnon college grad HA : pcollege grad < pnon college grad (d) H0 : µcollege grad = µnon college grad HA : µcollege grad < µnon college grad iii. Calculate the test statistic. 104 + 131 235 = = 0.284 438 + 389 827 qpooled = 1 − 0.284 = 0.716 ˆ p1 − p2 ˆ ˆ 0.237 − 0.337 −0.1 z=￿ =￿ = = −3.18 ppooled qpooled ˆ ˆ p ˆ q ˆ 0.0314 0.284∗0.716 + 0.284∗0.716 + pooled 2pooled 438 389 n1 n ppooled = ˆ iv. Calculate the p-value. p − value = P (z < −3.18) = 0.0007 v. What is the conclusion of the hypothesis test? Make sure to interpret your conclusion in context. Since p-value < α (0.05), we reject H0 . There is sucient evidence to suggest that the proportion of college graduates who responded do not know is lower than the proportion of non-college graduates who responded do not know. 8. A professor believes that students perform better on an introductory statistics exam if they are only allowed one sheet of notes (“cheat sheet”) compared to an “open book” exam (where they have access to all notes, textbook, etc.). To test his theory he randomly assigned the 50 students in his class to two groups: one group took the exam with just a “cheat sheet”, and the other group took the same exam “open book”. On average students in the “cheat sheet” group scored 6 points higher than the students in the “open book” group. (a) Write the hypotheses for testing the professor’s theory. H0 : µcheat sheet = µopen book HA : µcheat sheet > µopen book (b) To test these hypotheses the professor use...
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This document was uploaded on 12/04/2013.

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