stat_exam2_review_fall09 - PAM 2100 Exam #2 Review Problem...

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PAM 2100 Exam #2 Review Problem 1 A SRS of 1000 adults asks if they agree with the statement “I support President Obama.” Suppose that 90% of all US adults would agree if asked this question so the population parameter= 0.9. Round the standard deviation of the sample proportion p ˆ to four decimal places . Using that rounded number, what is the probability that the survey result differs from the truth about the population by more than 2 percentage points? (Use z- scores that actually appear in Table A. Round your final answer to four decimal places . Remember to express your answer as a proportion.)
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Melissa has invested 30% of her funds in T-bills and 70% of her funds in stocks. If X is the annual return on T-bills and Y the annual return on stocks, the portfolio rate of return is: R= 0.3X + 0.7Y The returns X and Y are random variables because they vary from year to year: X= annual return on T-bills μ X = 5 σ X = 4 Y= annual return on stocks μ Y = 12 σ Y = 6 correlation between X and Y ρ = -0.4 a) What is μ R ? b) What is σ R ? Round your final answer to four decimal places . 2
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This note was uploaded on 02/01/2010 for the course PAM 2100 taught by Professor Abdus,s. during the Spring '08 term at Cornell University (Engineering School).

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stat_exam2_review_fall09 - PAM 2100 Exam #2 Review Problem...

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