Tony is investigating the relationship between his daily energy bill in pounds (eee) and the average daily temperature in degrees (ttt) each day in the winter.
He finds that the equation of the regression line is e=7.3−0.4te = 7.3 - 0.4te=7.3−0.4t
Describe the correlation between Tony's bill and the average daily temperature.
Give an interpretation of the gradient of this regression line.
Explain why this model might not be appropriate for Tony's energy bill in the summer.
121 exam-style questions on OCR A Level Maths 2.2 Data Presentation and Interpretation, covering 2.2.1 Tables and diagrams for single variable data, 2.2.2 Area in a histogram, 2.2.3 Scatter diagrams and regression lines, 2.2.4 Informal interpretation of correlation, 2.2.5 Correlation and causation, 2.2.6 Measures of average and spread, 2.2.7 Calculations of mean and standard deviation, 2.2.8 Outliers, 2.2.9 Selecting or critiquing data presentation, and 2.2.10 Cleaning data. Each one has a worked solution and a mark scheme showing where the marks go.