SOLUTION: If the mean is 76 and the Standard Deviation is 6 how many students scored below a 70 on their test A. 24.3 B. 15.9 C. 18.4 D. 19.7 Help.(:?

Algebra ->  Probability-and-statistics -> SOLUTION: If the mean is 76 and the Standard Deviation is 6 how many students scored below a 70 on their test A. 24.3 B. 15.9 C. 18.4 D. 19.7 Help.(:?      Log On


   

Question 632090: If the mean is 76 and the Standard Deviation is 6 how many students scored below a 70 on their test
A. 24.3
B. 15.9
C. 18.4
D. 19.7
Help.(:?
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi,

If the mean is 76 and the Standard Deviation is 6 how many students scored below a 70 on their test

  z = (70-76)/6 = -1   using Excel function: NORMSDIST(-1) = .1587   

 P(x < 70) =  15.9 %

 15.9% of the students scored below 70 on their test