As Many as 20% of All Americans Contract Influenza Each

Multiple Choice

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 standard deviation of the sampling distribution?

A) 0.0045
B) 0.0195
C) 0.0200
D) 0.8125