SOLUTION: Hello, My question is: A national test has a mean of 400 and S.D. of 50. What is the prob. a score is greater than 500? Thanks so much!! Amy

Algebra ->  Probability-and-statistics -> SOLUTION: Hello, My question is: A national test has a mean of 400 and S.D. of 50. What is the prob. a score is greater than 500? Thanks so much!! Amy      Log On


   

Question 387010: Hello,
My question is: A national test has a mean of 400 and S.D. of 50. What is the prob. a score is greater than 500?
Thanks so much!!
Amy
Found 2 solutions by stanbon, ewatrrr:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
My question is: A national test has a mean of 400 and S.D. of 50. What is the prob. a score is greater than 500?
----
z(500) = (500-400)/50 = 2
---
P(x > 500) = P(z > 2) = 0.0228
===================================
Cheers,
Stan H.

Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!


Hi

*Note: z+=+blue%28x+-+mu%29%2Fblue%28sigma%29

     z+=+%28500+-+400%29%2F%2850%29

  z = 2    NORMSDIST(2) = .97725  using Excel function

  P(z > 2) = 1 - .97725 =.02275