The ambient temperature, T ∘CT\,^\circ\text{C}T∘C, and the cooling time, CCC minutes, required for a specialized industrial freezer to freeze a specific chemical sample were recorded on 6 different operating days. The data is summarized in the table below.
| Day | 1 | 2 | 3 | 4 | 5 | 6 |
|---|---|---|---|---|---|---|
| TTT | 20 | 22 | 25 | 28 | 30 | 31 |
| CCC | 14 | 16 | 21 | 26 | 32 | 35 |
Calculate the values of SCCS_{CC}SCC, STCS_{TC}STC and STTS_{TT}STT for these data.
Calculate the product moment correlation coefficient (PMCC) for these data.
Interpret your value of the PMCC in the context of the relationship between ambient temperature and cooling time.
On a suitable grid, draw a scatter diagram of cooling time against ambient temperature for these 6 days.
Determine the equation of the regression line of CCC on TTT in the form C=a+bTC = a + bTC=a+bT.
Use your regression line to estimate the cooling time required when the ambient temperature is 27 ∘C27\,^\circ\text{C}27∘C.
202 exam-style questions on Edexcel A Level Maths Regression, Correlation and Hypothesis Testing, covering 1.1 Exponential Models, 1.2 Measuring Correlation, and 1.3 Hypothesis Testing for Zero Correlation. Each one has a worked solution and a mark scheme showing where the marks go.