About 6% of the population has a particular genetic mutation. 400 people are randomly selected. Find the standard deviation for the number of people with the genetic mutation in such groups of 400.

Question

Please help

Answer 1

Hi Tatihana,

This is a binomial distribution since you have two outcomes, "success" (genetic mutation) and "failure" (not). The formula for standard deviation for this distribution is:

sigma=sqrt(n*p*(1-p))

sigma=population standard deviation

n=sample size

p=probability of "success"

1-p=probability of "failure"

For this problem,

n=400

p=0.06

1-p=0.94

sigma=sqrt(n*p*(1-p))

sigma=sqrt(400*0.06*0.94)

sigma=4.750

I hope this helps.