The expected value (mean) of a binomial variable is 15. The number of trials is 20. The probability of "success" is:
A).25
B).50
C).75
D).30

Question

Quizplus · Accepted Answer

We can use the formula for the expected value of a binomial variable: 
E(X) = np, where n is the number of trials and p is the probability of success. 
Substituting the given values, we get: 
15 = 20p 
Solving for p, we get: 
p = 15/20 = 0.75 
Therefore, the probability of success is 0.75, which is answer choice C.

The Expected Value (Mean) of a Binomial Variable Is 15