A psychologist investigates whether completing a warm-up puzzle improves performance on a second puzzle. All the participants are aged 14 to 16 and belong to the same cultural community in the UK. The psychologist concludes that the findings apply to teenagers in every country.
The psychologist expects the warm-up puzzle to improve performance. When giving instructions, the psychologist uses an encouraging tone with the warm-up group and a neutral tone with the group that does not complete a warm-up puzzle.
Explain one source of bias arising from the selection of participants and how it limits the psychologist's conclusion.
Explain one different source of bias arising from the way the psychologist conducts the study and how it may affect the results.
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.