SOLUTION: 7) The age of student are normally distributed with a mean of 25 and a standard deviation of 4.25. If a student is chosen at random, what is the probability that : a) THE student

Algebra ->  Probability-and-statistics -> SOLUTION: 7) The age of student are normally distributed with a mean of 25 and a standard deviation of 4.25. If a student is chosen at random, what is the probability that : a) THE student       Log On


   

Question 379936: 7) The age of student are normally distributed with a mean of 25 and a standard deviation of 4.25. If a student is chosen at random, what is the probability that :
a) THE student age is at least 27
b) THE student age is between 26 and 30
Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
Here mu+=+25 and sigma+=+4.25.

a) P%28X+%3E=+27%29+=+P%28%28X+-+mu%29%2Fsigma+%3E=+%2827+-+25%29%2F4.25+=+0.47%29. Hence P%28X+%3E=+27%29+=+P%28Z+%3E=0.47%29.


b) . Hence P(26 < X < 30) = P(0.235 < Z < 1.176)
In either case, just use a usual standard normal table to find the probabilities.