A normal distribution has a mean of µ = 70 with σ = 12.If one score is randomly selected from this distribution,what is the probability that the score will be greater than X = 79?
A)0.7734
B)0.2266
C)0.2734
D)0.3085

Question

A normal distribution has a mean of µ = 70 with σ = 12.If one score is randomly selected from this distribution,what is the probability that the score will be greater than X = 79?​
A)​0.7734
B)​0.2266
C)​0.2734
D)​0.3085

Quizplus · Accepted Answer

To calculate this probability, we need to standardize the score using the Z-score formula:
Z = (X - µ) / σ
Z = (79 - 70) / 12
Z = 0.75
Then, we look up the probability to the right of Z = 0.75 in the standard normal distribution table, which is 0.2266. Therefore, the probability of selecting a score greater than X = 79 is 0.2266.

A Normal Distribution Has a Mean of µ = 70