Nadia is investigating whether there is a correlation between the age of a second-hand car, in years, and its market value, in pounds.
Suggest a suitable null hypothesis and a suitable alternative hypothesis for a two-tailed test.
Nadia takes a random sample of 18 second-hand cars and obtains a product moment correlation coefficient of -0.45.
For n=18n = 18n=18, the critical value for a two-tailed test at the 5% level for the population correlation coefficient is 0.4683.
Carry out the hypothesis test at the 5% significance level.
244 exam-style questions on AQA A Level Maths 2.2 L: Data presentation and interpretation, covering 2.2.1 Single-variable data diagrams, 2.2.2 Scatter diagrams and correlation, 2.2.3 Central tendency, variation and standard deviation, 2.2.4 Outliers and cleaning data, and 2.2 L: Data presentation and interpretation. Each one has a worked solution and a mark scheme showing where the marks go.