SOLUTION: A statistical analysis of telephone calls made by a company indicates that the length of these calls is normally distributed , with mean 260 seconds and SD 40 seconds 1) what is t

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Question 898648: A statistical analysis of telephone calls made by a company indicates that the length of these calls is normally distributed , with mean 260 seconds and SD 40 seconds
1) what is the probability that a call lasted less than 190 seconds ?
2) what is the probability that a call lasted between 140 and 190 seconds?
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi

z = (190-260)/40 = -70/40 = -7/4 = -1.75

z = (140-260)/40 = -120/40 = -3

1)P(z < -1.75) = .0401   0r 4.01%

2) P(x < -1.75) - P(x<-3) = .0401 - .0013 = .0388  Or 3.88%

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