A psychologist tests whether background music affects recall. The music condition is tested in the afternoon in a room next to a noisy corridor. The silence condition is tested in the morning in a quiet room. The silence condition recalls more words.
Explain why the psychologist cannot conclude that the music caused the difference in recall.
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.