A company's occupational health department investigated the effectiveness of a new ergonomic vertical mouse designed to reduce wrist strain. They recruited a volunteer sample of 40 software developers from a single department in their London office. 20 of these volunteers were randomly assigned to use the ergonomic mouse for a month, while the remaining 20 continued using a standard mouse. At the end of the month, all 40 participants completed a questionnaire assessing their level of wrist discomfort.
Explain how this study might have been improved by using a stratified sample of employees from the entire international company instead of the original sample.
689 exam-style questions on AQA A Level Psychology Scientific processes. Each one has a worked solution and a mark scheme showing where the marks go.