Consider a normal population with a mean of 10 and a variance of 4.Find P(X 18).
A)1.00
B)0.00
C).9772
D).0228

Question

Consider a normal population with a mean of 10 and a variance of 4.Find P(X > 18).
A)1.00
B)0.00
C).9772
D).0228

Quizplus · Accepted Answer

Since the distribution is normal, we can use the z-score formula: Z = (X - μ) / σ.

Plugging in the values, we get: 
Z = (18 - 10) / √4 = 4

Looking up the z-score of 4 in a standard normal distribution table, we find that the probability of getting a value greater than that is basically 0 (to the nearest hundredth), which corresponds to choice B.

Consider a Normal Population with a Mean of 10 and a Variance