Question 468275: Best Electronics, Inc. offers a “no hassle” returns policy. The number of items returned
per day follows the normal distribution. The mean number of customer returns is 10.3
per day and the standard deviation is 2.25 per day.
a. In what percent of the days are there 8 or fewer customers returning items?
b. In what percent of the days are between 12 and 14 customers returning items?
c. Is there any chance of a day with no returns?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Best Electronics, Inc. offers a “no hassle” returns policy. The number of items returned per day follows the normal distribution.
The mean number of customer returns is 10.3
per day and the standard deviation is 2.25 per day.
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a. In what percent of the days are there 8 or fewer customers returning items?
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z(8) = (8-10.3)/2.25 = -1.0222
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%(x <= 8) = %(z <= -1.0222) = 15.33%
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b. In what percent of the days are between 12 and 14 customers returning items?
Normalcdf(12,14,10.3,2.25) = 17.49%
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c. Is there any chance of a day with no returns?
z(0) = (0-10.3)/2.25 = -4.5778
--
%(x <= 0) = %(z <--4.5778) = 0.00023518%
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Cheers,
Stan H.
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