Convert between different coding systems

Given coded sums with one constant (e.g., Σ(x - c₁)) and asked to find coded sums with a different constant (e.g., Σ(x - c₂)), or convert between linear transformations like y = (x - a)/b.

1 questions

Edexcel S1 2015 June Q2
2. An estate agent recorded the price per square metre, \(p \pounds / \mathrm { m } ^ { 2 }\), for 7 two-bedroom houses. He then coded the data using the coding \(q = \frac { p - a } { b }\), where \(a\) and \(b\) are positive constants. His results are shown in the table below.
\(p\)1840184818301824181918341850
\(q\)4.04.83.02.41.93.45.0
  1. Find the value of \(a\) and the value of \(b\) The estate agent also recorded the distance, \(d \mathrm {~km}\), of each house from the nearest train station. The results are summarised below. $$\mathrm { S } _ { d d } = 1.02 \quad \mathrm {~S} _ { q q } = 8.22 \quad \mathrm {~S} _ { d q } = - 2.17$$
  2. Calculate the product moment correlation coefficient between \(d\) and \(q\)
  3. Write down the value of the product moment correlation coefficient between \(d\) and \(p\) The estate agent records the price and size of 2 additional two-bedroom houses, \(H\) and \(J\).
    HousePrice \(( \pounds )\)Size \(\left( \mathrm { m } ^ { 2 } \right)\)
    \(H\)15640085
    \(J\)17290095
  4. Suggest which house is most likely to be closer to a train station. Justify your answer.