Mathematics
carlosalfonsoz9
34

The scores of a high school entrance exam are approximately normally distributed with a given mean = 82.4 and standard deviation = 3.3. What percentage of the scores are between 75.8 and 89?

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(1) Answers
sassymissy

P(75.8 < X < 89) = P(X < 89) - P(X < 75.8) = P(z < (89 - 82.4)/3.3) - P(z < (75.8 - 82.4)/3.3) = P(z < 2) - P(z < -2) = 2P(z < 2) - 1 = 2(0.97725) - 1 = 1.9545 - 1 = 0.9545

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