Z = (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 proportion/probability of that Z score.
IQ scores are normally distributed with a mean of 100 and a standard deviation of 15. What is the probability that a random sample of 20 people have a mean IQ score greater than 110? (Round to 4 decimal places)
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