Stratified Sampling

Question 1

What does stratified sampling use

Answer 1

Proportional representation

Question 2

What does stratified sampling give the groups in a population

Answer 2

The amount of representation that is proportional to how big they are in population

Question 3

When is stratified sampling useful

Answer 3

When different groups are like to give different results

Question 4

Pros of stratified sampling

Answer 4

If you have easy to define categories in the population it is likely to give you a representative sample
Can compare results from different groups

Question 5

Cons of stratified sampling

Answer 5

Isn’t useful when there aren’t any obvious categories or when categories are had to define
Can be expensive because of the extra detail involved

Question 6

Stratified sample equation

Answer 6

Number in category / total number X sample size

Question 7

Method for choosing stratified sample

Answer 7

Split population into categories
Calculate number to sample from each category Number in category / total number X sample size
Use random sampling to chose sample members from each category