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.
316 exam-style questions on OCR A Level Maths 2.5 Statistical Hypothesis Testing, covering 2.5.1 The language of hypothesis testing, 2.5.2 Hypothesis test for a binomial proportion, 2.5.3 Inference and significance level, 2.5.4 Sample mean as a random variable (A-level only), 2.5.5 Hypothesis test for the mean of a normal distribution (A-level only), 2.5.6 Pearson's product-moment correlation coefficient, and 2.5.7 Hypothesis test using Pearson's coefficient (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.