Asha is investigating the relationship between the daily electricity cost for heating her greenhouse in pounds (ccc) and the average daily temperature in degrees Celsius (ttt) during December.
She finds that the equation of the regression line is c=8.4−0.35tc = 8.4 - 0.35tc=8.4−0.35t.
Describe the correlation between Asha's electricity cost and the average daily temperature.
Give an interpretation of the gradient of this regression line.
Explain why this model might not be appropriate for Asha's electricity cost in the summer.
8 exam-style questions on Edexcel AS 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.