A worldwide organization of academics claims that the mean IQ score of its members is 118...

A worldwide organization of academics claims that the mean IQ score of its members is 118 , with a standard deviation of 15 . A randomly selected group of 35 members of this organization is tested, and the results reveal that the mean IQ score in this sample is 115.2 . If the organization's claim is correct, what is the probability of having a sample mean of 115.2 or less for a random sample of this size? Carry your intermediate computations to at least four decimal places. Round your answer to at least three decimal places.

Expert Solution

µ =    118
σ =    15
n=   35

X =   115.20

Z =   (X - µ )/(σ/√n) = (   115.2   -   118   ) / (   15   / √   35   ) =   -1.104

P(X ≤   115.2   ) = P(Z ≤   -1.104   ) =   0.1347                       (answer)

excel formula for probability from z score is =NORMSDIST(Z)

orchestra answered 1 year ago

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