A psychologist investigates whether room lighting affects attention. Twelve adult trainee electricians complete a symbol-search task in a dimly lit room at the end of their training day. A different twelve adult trainee electricians complete the same task in a brightly lit room at the start of their training day. Before each group begins, the psychologist says that she expects bright lighting to produce higher scores. The brightly lit group scores more highly, so the psychologist concludes that bright lighting improves attention in adults' everyday lives.
Evaluate the validity of the psychologist's study.
173 exam-style questions on OCR GCSE Psychology 7.3 Analysing Research, covering 7.3.1 Types of Data, 7.3.2 Measures of central tendency, 7.3.3 Other descriptive statistics, 7.3.4 Tables, Charts and Graphs, 7.3.5 Reliability, 7.3.6 Validity and effects on validity, and 7.3.7 Sources of bias. Each one has a worked solution and a mark scheme showing where the marks go.