A researcher investigates whether lighting affects proofreading accuracy. Forty participants proofread the same page containing 30 errors. Twenty participants work in bright lighting and twenty work in dim lighting. Before starting, they are told that the study investigates the effect of lighting on proofreading.
Afterwards, participants are asked whether they thought the researcher expected their lighting condition to produce greater accuracy.
| Lighting condition | Number who thought their condition was expected to produce greater accuracy |
|---|---|
| Bright | 16 |
| Dim | 10 |
Explain the threat to validity created by participants guessing which result the researcher expected. Use the questionnaire results to predict how this threat could affect the difference in proofreading accuracy between the two conditions.
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.