If µ = 400 and s = 100 the probability of selecting at random a score less than or equal to 370 equals _________.
A) 0.1179
B) 0.6179
C) 0.3821
D) 0.8821

Question

Quizplus · Accepted Answer

To calculate the probability we need to standardize the score:

z = (X - µ)/s

z = (370 - 400)/100 = -0.3

Using a standard normal distribution table, we find that the probability of z ≤ -0.3 is 0.3821. Therefore, the probability of selecting at random a score less than or equal to 370 is 0.3821 or 38.21%.

If µ = 400 and S = 100 the Probability