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.
355 exam-style questions on OCR (MEI) A Level Maths 2.5 Statistical Hypothesis Testing, covering 2.5.1 Process and language of hypothesis testing, 2.5.2 When to apply 1-tail and 2-tail tests, 2.5.3 Significance level and incorrect rejection, 2.5.4 Null and alternative hypotheses (binomial), 2.5.5 Conduct a binomial hypothesis test, 2.5.6 Critical and acceptance regions (binomial), 2.5.7 Distribution of the sample mean (A-level only), 2.5.8 Hypothesis test for a single mean (A-level only), 2.5.9 Critical and acceptance regions (mean) (A-level only), 2.5.10 Correlation as closeness to a straight line (A-level only), 2.5.11 Inference using a correlation coefficient (A-level only), and 2.5 Statistical Hypothesis Testing. Each one has a worked solution and a mark scheme showing where the marks go.