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March 28, 2015

March 28, 2015

Posted by **m elissa** on Sunday, May 20, 2012 at 6:24pm.

Assume that the mean score on a certain aptitude test across the nation is 100, and that the standard deviation is 20 points. Find the probability that the mean aptitude test score for a randomly selected group of 150 8th graders is between 99.5 and 100.5.

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**PsyDAG**, Monday, May 21, 2012 at 10:38amZ = (score-mean)/SEm

SEm = SD/√n

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportions related to the Z scores.

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