A random sample of 40 oak trees was studied by a biologist. She recorded the height hhh in meters and the trunk diameter ddd in centimeters of each tree.
The following summary statistics were calculated from these data:
∑h=680,∑h2=11776,∑d=1440,∑hd=25012,Sdd=2240 \sum h = 680, \quad \sum h^2 = 11776, \quad \sum d = 1440, \quad \sum hd = 25012, \quad S_{dd} = 2240 ∑h=680,∑h2=11776,∑d=1440,∑hd=25012,Sdd=2240Find ShhS_{hh}Shh and ShdS_{hd}Shd.
Calculate, to 3 significant figures, the product moment correlation coefficient between hhh and ddd.
Give an interpretation of your coefficient in the context of the biologist's study.
157 exam-style questions on AQA A Level Maths 2.2.2 Scatter diagrams and correlation. Each one has a worked solution and a mark scheme showing where the marks go.