Question 647523
The heights of 18-year-old men are approximately normally distributed with mean 68 inches and standard deviation 3 inches. What is the probability that the height of an 18-year-old man selected at random is between 64 inches and 66 inches.
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When you need to measure propability or percentage, you need to use 
the z-scale.
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z(64) = (64-68)/3 = -1.3333
z(66) = (66-68)/3 = -0.6667
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P(64 <= x <= 66) = P(-1.33 <= z <= -0.67) 
= normalcdf(-1.3333,-0.6667) = 0.1613
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Cheers,
Stan H.
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a. .1597
b. .2017
c. .3677
d. .8403
e. .3403