A linear regression model for the braking distance y y\,y metres of a car travelling at speed x x\,x km/h is y=0.011x2+0.18x−2.4y=0.011x^2+0.18x-2.4y=0.011x2+0.18x−2.4, for 40≤x≤10040\leq x\leq10040≤x≤100.
Use the model to estimate the braking distance at 80 km/h.
Explain why the model should not be used to estimate the braking distance at 130 km/h.
A car travelling at 80 km/h has an observed braking distance of 86 m. Find its residual.
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.