A scatter diagram of electricity use against outdoor temperature is U-shaped: use is high on very cold days, low on mild days and high on very hot days.
Explain why the data could be described as having zero linear correlation despite the clear pattern.
Explain why a linear regression model would be unsuitable.
Suggest a refinement to the model or analysis.
105 exam-style questions on WJEC A Level Maths 2.2 Data presentation and interpretation, covering 2.2.1 Data presentation and interpretation, 2.2.2 Data presentation and interpretation, 2.2.3 Data presentation and interpretation, 2.2.4 Data presentation and interpretation, 2.2.5 Data presentation and interpretation, 2.2.6 Data presentation and interpretation, 2.2.7 Data presentation and interpretation, 2.2.8 Data presentation and interpretation, and 2.2 Data presentation and interpretation. Each one has a worked solution and a mark scheme showing where the marks go.