Using the large data set Colin studied the relationship between rainfall (rrr) and temperature (ttt) in Camborne. He took a sample of 12 days from May and June 1987 and obtained the following results.
| Rainfall (cm) | 3.1 | 0.1 | 6 | 2.2 | 0.3 | 4.2 | 1.7 | 7.5 | 0.1 | 7.1 | 3.9 | 3.1 |
| Temperature (°C) | 10.7 | 8.9 | 8.8 | 9.2 | 11.1 | 10.2 | 12.6 | 10.4 | 11.3 | 11.6 | 12.8 | 13.5 |
Use your knowledge of the large data set to explain why it is unlikely that Colin used a random sample.
Colin used a computer program to obtain the following statistics for Rainfall
Lower limit=−3.6 \text{Lower limit} = -3.6 Lower limit=−3.6 Upper limit=9.6 \text{Upper limit} = 9.6 Upper limit=9.6The lower limit is given by Q1−1.5IQRQ_1-1.5IQRQ1−1.5IQR and the upper limit is given by Q3+1.5IQRQ_3+1.5IQRQ3+1.5IQR. Determine the interquartile range.
Plot the information on a scatter graph
Explain why a linear regression model may not be suitable for this data.
46 exam-style questions on Edexcel A Level Maths Correlation, covering 4.1 Correlation and 4.2 Linear Regression. Each one has a worked solution and a mark scheme showing where the marks go.