.33 = .39-.06 = .39 - .04*1.5
so, that is 1.5 std below the mean.
Now consult your Z table and find that
P(Z > -1.5) = .9332
.9332*500 = 466.6
The diameters of pencils produced by a certain machine are normally distributed with a mean of 0.39 inches and a standard deviation of 0.04 inches.
If 500 pencils are selected how many would you expect to have a diameter more than 0.33 inches?
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Thank you so much. I greatly appreciate it.
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