A researcher records the distance x x\,x km cycled each week and resting pulse rate y y\,y beats per minute for a random sample of adults. The regression line of y y\,y on x x\,x is y=78−0.42xy=78-0.42xy=78−0.42x. One adult cycles 40 km and has a resting pulse rate of 68 beats per minute.
Find the predicted resting pulse rate for this adult.
Find the residual.
Explain why the regression line cannot establish that cycling farther causes a lower resting pulse rate.
278 exam-style questions on CCEA A Level Maths 2.5 Data presentation and interpretation, covering 2.5.1 Data presentation and interpretation, 2.5.2 Data presentation and interpretation, 2.5.3 Data presentation and interpretation, 2.5.4 Data presentation and interpretation, 2.5.5 Data presentation and interpretation, 2.5.6 Data presentation and interpretation, 2.5.7 Data presentation and interpretation, 2.5.8 Data presentation and interpretation, 2.5.9 Data presentation and interpretation, and 2.5 Data presentation and interpretation. Each one has a worked solution and a mark scheme showing where the marks go.