The parent distribution of x is normal with mean 80 and std. dev. 9

sample size n = 25, mean (pop) of mean (samp) = 80, std dev (pop) of mean (samp) = 9/5 = 1.8

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x = sample mean

find

A. P(62 < x < 80)

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B. P(71 < x < 77)

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C. x' such that P(x > x') = .05

Thanks in advance if anyone can help me with this