P(xbar < 20.6) = P(z < (xbar - mu)/(STD/sqrt(sample size))
P(z < (20.6 - 20)/(1.8/sqrt(25)) = P(z < 1.66) = 0.9515
Nate G.
asked 04/21/22A manufacturer knows that their items have a normally distributed length, with a mean of 20 inches, and standard deviation of 1.8 inches.
If 25 items are chosen at random, what is the probability that their mean length is less than 20.6 inches?
P(xbar < 20.6) = P(z < (xbar - mu)/(STD/sqrt(sample size))
P(z < (20.6 - 20)/(1.8/sqrt(25)) = P(z < 1.66) = 0.9515
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