section_problems_2_fall11(1) - Use z-scores that are...

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Section Problems #2 From book: 1.145 (page 73) Express your answers as proportions instead of percents. Round your final answers to four decimal places. For part c , use the z -score associated with the cumulative proportion that is as close as possible to 0.8. #1) ACT scores are distributed normally with a mean μ = 26 and a standard deviation σ = 4.8. What score would a student have to achieve in order to score as close as possible to the 70 th percentile (according to Table A)? What score would a student have to achieve in order to score as close as possible to the 20 th percentile (according to Table A)? Use z -scores that are actually listed in Table A. Round your answers to three decimal places . #2) ACT scores are distributed normally with a mean μ = 26 and a standard deviation σ = 4.8. How high must a student score in order to place in the top 20% of students taking the ACT test (according to Table A)? How high must a student score in order to place in the top 10% of students taking the ACT test (according to Table A)?
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Unformatted text preview: Use z-scores that are actually listed in Table A. Round your answer to three decimal places . #3) The mean of x = 11 and the standard deviation of x = 7. The variable x is linearly transformed such that x new = 6 x . What is the mean of x new ? What is the standard deviation of x new ? #4) The mean of x = 10 and the standard deviation of x = 4. The variable x is linearly transformed such that x new = a + bx . The mean of x new = 35 and standard deviation of x new = 12. Suppose b is a positive number. What does a equal? What does b equal? #5) The median of x = 8 and the IQR of x = 9. The variable x is linearly transformed such that x new = 5 + x . What is the median of x new ? What is the IQR of x new ? #6) The mean of x = 6 and the standard deviation of x = 2. The variable x is linearly transformed such that x new = a + bx . The mean of x new = 75 and the variance of x new = 16. Suppose b is a positive number. What does a equal? What does b equal?...
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