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# Help with Stats & Prob?

a) Let Y be a population with variance 25 and mean 75. Find the probability that in a random sample of 64 the sample mean will be between 74 and 77.

b) Find the probability that the sample standard deviation will be between 4.5 and 6 assuming Y is a normal population

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- Julius NLv 77 years agoFavorite Answer
a) z = ( x - μ ) / (σ÷√η)

P (74 < x < 77) = P (-1.6 < z < 3.2) = 0.9445

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