Question 264417
The time needed to complete the final examination of MGSC 301 is normally distributed with a mean of 120 minutes and a standard deviation of 12 minutes. 
a.
What is the probability that a student will finish the examination in two hours or more?
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2 hrs is 120 minutes which is the mean.
P(x>= 120) = 0.5000
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b.
What is the probability that a student will finish the examination in more than 100 minutes but less than 150 minutes?
z(100) = (100-120)/12 = -20/12 = -1.667
z(150) = (150-120)/12 = 30/12 = 2.5
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P(100< x < 150) = P(-1.667 < z < 2.5) = 0.9460
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c.
What is the probability that a student will 
finish the examination in more than 140 minutes?
z(140) = (140-120)/12 = 1.667
P(z > 140) = P(z> 1.667) = 0.0478
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Cheers,
Stan H.