An environmentalist recorded the engine size (e e\,e litres) and CO2 CO_2\,CO2 emissions (c c\,c g/km) of 12 different car models. The results are shown in the table.
| Engine Size (L) | 1.0 | 1.2 | 1.4 | 1.6 | 2.0 | 2.2 | 2.5 | 3.0 | 3.5 | 4.0 | 4.5 | 5.0 |
| Emissions (g/km) | 98 | 115 | 122 | 130 | 145 | 160 | 178 | 210 | 235 | 260 | 290 | 320 |
Draw a scatter graph for this information.
Give an interpretation of the correlation between the engine size and CO2 CO_2\,CO2 emissions.
The equation of the regression line is c=55.4e+42.1c = 55.4e + 42.1c=55.4e+42.1.
Give an interpretation of the gradient of this regression line.
The product moment correlation coefficient is calculated to be 0.79.
Stating your hypotheses clearly test, at the 5% significance level, whether there is a positive correlation between engine size and CO2 CO_2\,CO2 emissions.
Determine whether you would reach the same conclusion at the 1% significance level.
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.