SOLUTION: For these problems, assume that the length of a large population of service calls last a mean of μ=15 minutes with a standard deviation of σ=6.2 minutes and X is the length of a

Question 1197777: For these problems, assume that the length of a large population of service calls last a mean of μ=15 minutes with a standard deviation of σ=6.2 minutes and X is the length of a randomly-selected service call and X can be modeled by a Normal Distribution. Round each answer to 2 decimal places.
a. What proportion of service calls last more than 8 minutes?
b. P(X<8)=
c. Would it be unusual to find a service call to last at most 8 minutes ?
No, it is not rare
Yes, it is rare

d. The 27th percentile is:
Answer by ewatrrr(24785) (Show Source): You can put this solution on YOUR website!


Hi  
Normal Distribution: µ = 15 and σ = 6  
Using TI or similarly an inexpensive calculator like an Casio fx-115 ES plus
a. P(x>8) = 1 - P(x ≤ 8) = 1 - normcdf(-9999, 8,6, 15) = 1 - .1217= .8783
b. Continuous Curve: P(x ≤ 8) = P(x < 8) = .1217***
c. Would it be unusual to find a service call to last at most 8 minutes
Yes, it is rare***
Wish You the Best in your Studies.

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