SOLUTION: Assume that blood pressure readings are normally distributed with a mean of 118 and a standard deviation of 9. If one person is randomly selected, find the probability that his/her

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Question 965773: Assume that blood pressure readings are normally distributed with a mean of 118 and a standard deviation of 9. If one person is randomly selected, find the probability that his/her blood pressure will be greater than 120.
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Found 2 solutions by Fombitz, rothauserc:
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Find the z score.
Z=%28x-mu%29%2Fsigma=%28120-118%29%2F9
Z=0.222
Find the corresponding probability for that z-score.
P%5B1%5D=0.5879
That probability corresponds to blood pressures from 0 to 120 so you need to get the complement.
P=1-P%5B1%5D
P=1-0.5879
P=0.412

Answer by rothauserc(4718) About Me  (Show Source):
You can put this solution on YOUR website!
Probability(Pr) ( X > 120 ) = 1 - Pr ( X < 120 )
compute z-score for 120.
z-score = (120 - 118) / 9 = 0.222222222 approx .22
consult z-tables for probability associated with z-score .22, which is
0.5871, therefore
Pr ( X > 120 ) = 1 - 0.5871 = 0.4129 approx 0.41