SOLUTION: The average yearly snowfall in Deer Park is normally distributed with a mean of 55 inches. If the snowfall in Deer Park exceeds 60 inches in 15% of the years, what is the standard

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Question 540378: The average yearly snowfall in Deer Park is normally distributed with a mean of 55 inches. If the snowfall in Deer Park exceeds 60 inches in 15% of the years, what is the standard deviation?

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
The average yearly snowfall in Deer Park is normally distributed with a mean of 55 inches. If the snowfall in Deer Park exceeds 60 inches in 15% of the years, what is the standard deviation?
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Draw a picture of the normal curve with the given facts.
Find the z-value with a right tail of 15%.
invNorm(0.85) = 1.0364
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Use x = zs + u to find the standard deviation.
60 = 1.0364s + 55
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1.0364s = 5
s = 4.82 inches
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Cheers,
Stan H.
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