# Is there a formula for stratified sampling?

Mar 2, 2016

Yes, there is a formula for stratified sampling.

#### Explanation:

The formula for stratified sampling is as follows:
("group size")/("population size") times "sample size"

The formula is used to find the amount of people that exhibit a certain trait within a population.

For example, in a class of 40 students, in which 15 are male, and 25 are female, find the number of male students which, out of a sample of 5, got the highest grades.

Thus:
$\frac{15}{40} \times 5 = 1.875$, which, when rounded to 1 d.p gives 2.