An environmental study measures the nitrogen concentration, xxx mg/L, and the dissolved oxygen level, yyy mg/L, at 15 different sites along an industrial canal. The data are summarised as follows:
Sxx=2 400S_{xx} = 2\,400Sxx=2400 ∑y=1 020\sum y = 1\,020∑y=1020 ∑y2=72 400\sum y^2 = 72\,400∑y2=72400 Sxy=−1 950S_{xy} = -1\,950Sxy=−1950
Determine the value of SyyS_{yy}Syy.
Calculate the product moment correlation coefficient for these data, giving your answer to 3 significant figures.
Interpret the value of the correlation coefficient in the context of the study.
A scientist converts the nitrogen concentration into grams per litre, www, such that w=x1000w = \frac{x}{1000}w=1000x.
State the value of SwwS_{ww}Sww.
State the value of the product moment correlation coefficient between www and yyy.
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.