Problema Solution
in a set of 100 act scores, where the mean is 25 and the standard deviation is 3.32, how many scores are expected to be lower than 21.68?
Answer provided by our tutors
Assuming we have a normal distribution the Number of scores to be less than 21.68 is:
100 * P(X < 21.68) = 100* P(Z < (21.68 - 25)/3.32) = 100*P(Z < -1) = 100*(0.1587) = 15.87 or approximately 16 scores.