AQA S1 2009 January — Question 2

Exam BoardAQA
ModuleS1 (Statistics 1)
Year2009
SessionJanuary
TopicBivariate data
TypeCalculate r from raw bivariate data

2 A greengrocer sells bunches of 9 carrots at his Saturday market stall. Tom and Geri are two Statistics students who work on the stall. Each selects a bunch of carrots at random.
  1. At home, Tom measures the length, \(x\) centimetres, and the maximum diameter, \(y\) centimetres, of each carrot in his selected bunch with the following results.
    \(\boldsymbol { x }\)16.213.110.412.114.69.711.813.617.3
    \(\boldsymbol { y }\)4.23.94.73.33.72.43.13.52.7
    1. Calculate the value of the product moment correlation coefficient.
    2. Interpret your value in context.
  2. At her home, Geri measures the length, in centimetres, and the weight, in grams, of each carrot in her selected bunch and then obtains a value of - 0.986 for the product moment correlation coefficient. Comment, with a reason, on the likely validity of Geri's value.