Question 200682: The accountant department at Weston Materials, inc, a national manufacturer of unattached garages, reports that it takes two construction workers a mean of 32 hours and a standard deviation of 2 hours to erect the Red Barn model Assume the assemble times follow the normal distribution.
a) Determine the z values for 29 and 34 hours. What percent of the garage takes between 32 and 34 hours to erect?
b) What percent of the garage take between 29 hours and 34 hours to erect
c) What percent of the garage takes between 28.7 hours or less erect?
d) Of the garage, 5 percent take how mant hours or more to erect
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! The accountant department at Weston Materials, inc, a national manufacturer of unattached garages, reports that it takes two construction workers a mean of 32 hours and a standard deviation of 2 hours to erect the Red Barn model Assume the assemble times follow the normal distribution.
a) Determine the z values for 29 and 34 hours. What percent of the garage takes between 32 and 34 hours to erect?
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z(29) = (29-32)/2 = -3/2 = -1.5
z(34) = (34-32)/2 = 2/2 = 1
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b) What percent of the garage take between 29 hours and 34 hours to erect
P(29
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c) What percent of the garage takes between 28.7 hours or less erect?
Find the z-values of 28.7 and 0.
Then find the percentage between those two z values to get:
Ans: 4.95%
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d) Of the garage, 5 percent take how many hours or more to erect
The z value of 5% is -1.645
Find the x-value corresponding to z=-1.645
x = zs+u
x = -1.645*2 + 32
x = 28.71 hrs.
Ans: # of hours >= 28.71
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Cheers,
Stan H.
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