Solve the problem.
-The probability that a person has immunity to a particular disease is 0.2. Find the mean number who have immunity in samples of size 30.
A) 0.2
B) 6.0
C) 24.0
D) 15.0

Question

Quizplus · Accepted Answer

The probability of having immunity is 0.2. 
In a sample of size 30, the mean number with immunity is found by multiplying the probability by the sample size: 
0.2 x 30 = 6
Therefore, the mean number with immunity in a sample size of 30 is 6, which is represented by choice B.

Solve the Problem. -The Probability That a Person Has Immunity to a Particular