Question 577900
A worldwide organization of academics claims that the mean IQ score of 115 its members is , 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 114.4 . If the organization's claim is correct, what is the probability of having a sample mean of 114.4 or less for a random sample of this size
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t(114.4) = (114.4-115)/[15/sqrt(35)] = -0.2366
P(x-bar <= 114.4) 
= P(t<= -0.2366 when df = 34) 
= tcdf(-100,-0.2366,34) 
= 0.4072
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Cheers,
Stan H.
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