Given coefficient value only

Question provides the value of Spearman's coefficient and asks only to perform or interpret a hypothesis test, without requiring calculation of the coefficient.

1 questions · Standard +0.3

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WJEC Further Unit 2 2023 June Q5
12 marks Standard +0.3
  1. Give two circumstances where it may be more appropriate to use Spearman's rank correlation coefficient rather than Pearson's product moment correlation coefficient. [2]
  2. A farmer needs a new tractor. The tractor salesman selects 6 tractors at random to show the farmer. The farmer ranks these tractors, in order of preference, according to their ability to meet his needs on the farm. The tractor salesman makes a note of the price and power take-off (PTO) of the tractors.
    TractorFarmer's rankPTO (horsepower)Price (£1000s)
    A177·580
    B687·945
    C553·047
    D441·053
    E2112·060
    F390·061
    Spearman's rank correlation coefficient between the farmer's ranks and the price is 0·9429.
    1. Test at the 5% significance level whether there is an association between the price of a tractor and the farmer's judgement of the ability of the tractor to meet his needs on the farm. [4]
    2. Calculate Spearman's rank correlation coefficient between the farmer's rank and PTO. [4]
    3. How should the tractor salesman interpret the results in (i) and (ii)? [2]