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 503 and the standard deviation is 113. Assume the variable x is normally distributed.

a)what percent of the SAT verbal scores are less than 675?

b)if 1000 SAT verbal scores are randomly selected, about how many would you expect to be greater than 525?

In a survey of a group of men, the heights in the 20-29 age group were normally distributed, with a mean of 67.9 inches and a standard deviation of2.0 inches. A study participant is randomly selected. Complete parts (a) through (d) below. (a) Find the probability that a study participant has a height that is less than 67inches.

Explanation / Answer

Mean = 503 and std dev =113

x is normal

Hence if X<675, then z <1.52

Hence prob =0.5-0.4357

= 0.0643

= 6.43%

B) x<525 means z<0.194

Prob = 0.5753

57.53%

----------------------

Height of men of age group (20-29) X is N(67.9,2)

P(X<67) = P(Z<-0.098)=0.5-0.0398

= 0.4602

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