7 The relationship between the variables \(P\) and \(Q\) is modelled by the formula
\(Q = a P ^ { n }\)
where \(a\) and \(n\) are constants.
Some values of \(P\) and \(Q\) are obtained from an experiment.
- State appropriate quantities to plot so that the resulting points lie approximately in a straight line.
- Explain how to use such a graph to estimate the value of \(n\).