SOLUTION: X is a normal variate with mean 30 and standard deviation 5. Find the probabilities that 1. 26< X <40 2. x>45

Algebra ->  Probability-and-statistics -> SOLUTION: X is a normal variate with mean 30 and standard deviation 5. Find the probabilities that 1. 26< X <40 2. x>45      Log On


   

Question 373584: X is a normal variate with mean 30 and standard deviation
5. Find the probabilities that
1. 26< X <40
2. x>45
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!


Hi,

*Note: z+=+%28X+-+mu%29%2Fsigma

P(26< X <40)

z = 40-30/5 = 2

z = 26-30/5 = -.8

using the excel normdist functon

NORMSDIST(2)   = .97725

NORMSDIST(-0.8)= .21186

P(26< X <40) = .97725 - .21186  = .76539



P(x>45)

z = 45-40/5 = 1

NORMSDIST(1)= .841345

P(x>45) = 1 - .841345 = .15866