8.

Many people claim "at most 60% of residents in Maryland rank Costco above Whole Foods". You want to write a formal report to support this claim. You collected a random sample of 6 residents in your neighborhood and found that 4 of them prefer Costco. Which of the following is (approximately) a 90% condence interval for the population proportion p (of those who prefer Costco)? A) [0.4629, 0.7371] B) [0.4315, 0.5685] C) [0.3962, 0.6068] D) [0.3629, 0.6371] E) None of the above. Use the information in question 8, answer the following question: If you want to support your report by conducting a hypothesis test, how should you formulate the alternative hypothesis for your test? A)p2 0.6 B)p0.6 O Dip0.6 E)p70.6 Use the information in question 8 and 9, answer the following question: In the above, which of the following would improve the quality of your test? i) Raise the level of signicance, oz, from 0.1 to 0.8, so that it is relatively easy to reject the null. ii) Select sample randomly over Maryland instead of choosing people only in the local neighborhood. iii) Increase sample size from 36 to a much larger number. A) i) and ii) B) i) and iii) C) ii) and iii) D) i), ii) and iii) Which of the following statements is/are correct regarding linear regressions (with least square method) i) 95% Cl for )60 + 51x is wider than the 90% Cl. ii) R2 is always between 0 and 1 A) i) only B) ii) only C) Both i) and ii) D) Neither i) nor ii). Which of the following statements is/are correct regarding linear regressions (with least square method) i) Linear regressions can only t straight lines. ii) Causality between the y-variable and x-variable(s) can not be demonstrated by a simple linear regression, but can be demonstrated by a multiple linear regression. A) i) only B) ii) only C) Both i) and ii) D) Neither i) nor ii)