Topic assessment 1. From a recent census in a particular residential area it was found that 95% of residents had English as their main language and 30% of the population were under 18 years old. The local library wants to explore this issue and decides to create a sample of 200 people. (a) In a stratified sample, how many of the 200 people should be 18 years old or over and have a main language that is not English? [1] (b) Describe one difficulty of creating a stratified sample. [1] (c) Describe why a quota sample might be preferable to a stratified sample. [2]