As many as 20% of all Americans contract influenza each year. A sample of 400 randomly selected Americans is chosen and the number with influenza is recorded. Let X represent the number with influenza in the sample. If X = 75 individuals are found to have influenza, what is the sample proportion?

Question

Quizplus · Accepted Answer

The sample proportion is the number of individuals in the sample with influenza divided by the size of the sample:

sample proportion = number with influenza / sample size

Plugging in the numbers from the problem,

sample proportion = 75 / 400

simplifying,

sample proportion = 0.1875

Therefore, the answer is B.

As Many as 20% of All Americans Contract Influenza Each