Edexcel S1 2015 January — Question 5

Exam BoardEdexcel
ModuleS1 (Statistics 1)
Year2015
SessionJanuary
TopicLinear regression
TypeIdentify response/explanatory variables

  1. The resting heart rate, \(h\) beats per minute (bpm), and average length of daily exercise, \(t\) minutes, of a random sample of 8 teachers are shown in the table below.
\(t\)2035402545707590
\(h\)8885777571666054
  1. State, with a reason, which variable is the response variable. The equation of the least squares regression line of \(h\) on \(t\) is $$h = 93.5 - 0.43 t$$
  2. Give an interpretation of the gradient of this regression line.
  3. Find the value of \(\bar { t }\) and the value of \(\bar { h }\)
  4. Show that the point \(( \bar { t } , \bar { h } )\) lies on the regression line.
  5. Estimate the resting heart rate of a teacher with an average length of daily exercise of 1 hour.
  6. Comment, giving a reason, on the reliability of the estimate in part (e). The resting heart rate of teachers is assumed to be normally distributed with mean 73 bpm and standard deviation 8 bpm . The middle \(95 \%\) of resting heart rates of teachers lies between \(a\) and \(b\)
  7. Find the value of \(a\) and the value of \(b\).