Use the normal distribution of SAT critical reading scores for which the mean is

Question

Use the normal distribution of SAT critical reading scores for which the mean is 515 and the standard deviation is 117 . Assume the variable x is normally distributed. left parenthesis a right parenthesis

A) What percent of the SAT verbal scores are less than 600 ? Answer 600 - 515 / 117 = .73 = z-score 0.7673 = 100 x 0.7673 = 76.73

B) If 1000 SAT verbal scores are randomly selected, about how many would you expect to be greater than 525 ? You would expect that approximately __?__ SAT verbal scores would be greater than 525. (the answer is 466. How is this part calculated? I cannot figure it out for the life of me!) Please Help!

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Explanation / Answer

A)

z=(600-515)/117 = 85/117 = 0.726

P(z<0.726)=0.7662= 76.62% .............you can use Excel function =normsdist(0.726) you will get 0.7662

B)

z=(525-515)/117 = 10/117= 0.085

P(z>0.085) = 0.4659. Of 1000 people, 466 will score higher than 525

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