If there are 10,300 people in this community, what is the standard deviation of the number of people who suffer from insomnia?

Question

Consider the following binomial experiment: A study in a certain community showed that 9% of the people suffer from insomnia.

Answer 1

The standard deviation of a binomial is square root of (npq). 

 

Sqrt(10,300*.09*.91)=29.04

Answer 2

Hi Terah,

The standard deviation for a binomial experiment is sigma=sqr of npq = √(10,000)(.09)(.91) = 28.6