Stratified Sample - GCSE Psychology Definition

A stratified sample is a way of selecting people to take part in a study so that different groups are fairly represented in the sample. Imagine you want to find out what students in a school think about a new subject. If the school has more Year 11 students than Year 10, you wouldn’t select any student randomly because Year 11 might be over-represented. Instead, you create groups based on numbers per year group and pick the same proportion of students from each year as there are in the whole school. This way, the sample rets presents the target population, making the findings more generalisable.