The reaction times of 30 pupils are shown in the frequency table below.
0.2 to under 0.3 seconds: 5 0.3 to under 0.4 seconds: 12 0.4 to under 0.5 seconds: 9 0.5 to under 0.6 seconds: 4
Calculate the fraction of pupils whose reaction time was 0.4 seconds or more. Give your answer in its lowest terms.
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.