SOLUTION: Insurance companies have determined that US males between the ages of 16 and 24 drive an average of 10,718 miles each year with a standard deviation of 3763 miles. Assume the date

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Question 322995: Insurance companies have determined that US males between the ages of 16 and 24 drive an average of 10,718 miles each year with a standard deviation of 3763 miles. Assume the datea is normally distributed. For a randomly selected male in that age group, find the probability that he drives less than 12,000 miles per year...i have a formula that i used...i'm just confused because some questions say less than...and some say more than...just wanted to ensure i did this correctly: (12000-10718)/3763=.3407
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Insurance companies have determined that US males between the ages of 16 and 24 drive an average of 10,718 miles each year with a standard deviation of 3763 miles. Assume the datea is normally distributed. For a randomly selected male in that age group, per year...i have a formula that i used...i'm just confused because some questions say less than...and some say more than...just wanted to ensure i did this correctly: (12000-10718)/3763=.3407
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Good. That is the z-value of 12000
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"Find the probability that he drives less than 12,000 miles."
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Then P(x < 12000) = P(z < 0.3407) = normalcdf(-1000,0.3407) = 0.6333
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Cheers,
Stan H.