The mean score of a college entrance test is 519 the standar

The mean score of a college entrance test is 519; the standard deviation is 75. The scores are normally distributed. What percent of the students scored below 323?

Solution

So the percent of the students scored below 323 is

P(X<323) = P((X-mean)/s <(323-519)/75)

=P(Z<-2.61) = 0.0045 (from standard normal table)

i.e. 0.45%

Answer: About 0.45%