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Being a lit. student who doesn't even really know what all the math signs are, I have a question. It is probably super easy for anyone with q math iq higher than my room-temperature one.

The scores of students on ACT college entrance exams in recent years have had a mean of $\mu = 18.6$ and a standard deviation of $5.9$. Assuming that admitted students from a college have the same mean and standard deviation, find the probability that $50$ randomly chosen students would have a sample mean higher than $20$.

Thanks in advance!!

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If this is homework, please tag it as such. Do you have any ideas on where to start? What have been you're thoughts about the question thus far? –  fdart17 Mar 11 '11 at 4:32

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Hint: the expected mean of the sample is the same as the mean of the parent distribution. The variance of the mean goes down as 1/n. So how many standard deviations high would the sample have to be? See Estimation of Parameters in the Wikipedia page

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