An ecologist records soil salinity s s\,s mS cm−1^{-1}−1 and maximum grass height h h\,h cm at 10 sites. Nine points follow a strong negative linear pattern. The tenth point, Site Omega, lies well above this pattern. For the other nine sites, the correlation coefficient is -0.824.
Interpret the value -0.824 in context.
Explain why Site Omega should not automatically be deleted.
State the likely effect on the magnitude of the correlation coefficient if Site Omega is included, and justify your answer.
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.