Question 469011
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Suppose the scores of certain standardized tests are normally distributed with mean 500 and standard deviation 60.
8. (1 point) What percent of the test takers have a score of 440 or less? Round answer to four places after the decimal point.
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z(440) = (440-500)/60 = -1
%(x <= 440) = %(z <= -1) = normalcdf(-1,100) = 84.1345
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9. (1 point) What percent of the test takers have a score of 590 or more? Round answer to four places after the decimal point.
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Use the same process as above:
Ans: 6.6807
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10. (1 point) What percent of the test takers have a score between 440 and 590? Round answer to four places after the decimal point.
%(440 < x < 590) = %(-1 < z < 1.5) = normalcdf(-1,1.5) = 77.4538
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11. (1 point) Suppose a college will only admit students who score in the top 20% among all test takers, what will be the minimum required score be? Round answer to the nearest whole number.
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Find the z-value with a left tail of 80% = invNorm(0.8) = 0.8416
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Find the correspond score (x) using x = zs + u
x = 0.8416*60+400 = 550.50
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cheers,
Stan H.