OCR Further Statistics 2019 June — Question 1

Exam BoardOCR
ModuleFurther Statistics (Further Statistics)
Year2019
SessionJune
TopicLinear regression
TypeAssess validity of predictions

1 A set of bivariate data ( \(X , Y\) ) is summarised as follows.
\(n = 25 , \sum x = 9.975 , \sum y = 11.175 , \sum x ^ { 2 } = 5.725 , \sum y ^ { 2 } = 46.200 , \sum x y = 11.575\)
  1. Calculate the value of Pearson's product-moment correlation coefficient.
  2. Calculate the equation of the regression line of \(y\) on \(x\). It is desired to know whether the regression line of \(y\) on \(x\) will provide a reliable estimate of \(y\) when \(x = 0.75\).
  3. State one reason for believing that the estimate will be reliable.
  4. State what further information is needed in order to determine whether the estimate is reliable.