If a normally distributed group of test scores have a mean of 70 and a standard deviation of 12, find the percentage of scores that will fall below 50.

a. 4.75%
b. 45.25%
c. 6.75%
d. 35.54%

Question

If a normally distributed group of test scores have a mean of 70 and a standard deviation of 12, find the percentage of scores that will fall below 50.

a. 4.75%
b. 45.25%
c. 6.75%
d. 35.54%

anonymous · Answer

z = (50 - 70)/12 = -1.67.
P(z<-1.67) = 0.04746.

The percentage of scores below 50 (which is the same as the probability a score is less than 50) is 4.75%

anonymous · Answer

OK I thought that was the answer that I was getting