The monthly rainfall, xxx mm, and the average wind speed, yyy knots, were recorded in 10 coastal locations over a period of one month. The data are summarised below:
Sxx=4 225S_{xx} = 4\,225Sxx=4225 ∑y=145\sum y = 145∑y=145 ∑y2=2 250\sum y^2 = 2\,250∑y2=2250 Sxy=652.5S_{xy} = 652.5Sxy=652.5
Find SyyS_{yy}Syy.
Calculate, to 3 significant figures, the product moment correlation coefficient for these data.
Give an interpretation of your coefficient in context.
A researcher decides to use the variable www to represent rainfall in centimetres, where w=x10w = \frac{x}{10}w=10x.
Write down the value of SwwS_{ww}Sww.
Write down 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.