x is a normally distributed random variable with a mean of 22 and a standard deviation of 5.The probability that x is less than 9.7 is
A) 0.000
B) 0.4931
C) 0.0069
D) 0.9931

Question

Quizplus · Accepted Answer

Using the Z-score formula,
Z = (9.7 - 22) / 5 = -2.46

Then, we can look up the probability in a standard normal distribution table or use a calculator:

P(Z < -2.46) = 0.0069

Therefore, the probability that x is less than 9.7 is 0.0069 or approximately 0.7%. Hence, the best choice is (C).

X Is a Normally Distributed Random Variable with a Mean