5 The speed \(v \mathrm {~ms} ^ { - 1 }\) of a car at time \(t\) seconds after it starts to accelerate was measured at 1 -second intervals. The results are shown in the following diagram.
\includegraphics[max width=\textwidth, alt={}, center]{d5843350-52f9-4fed-adf4-86ceb958033f-3_661_1186_1078_443}

1. State whether \(t\) or \(v\) or neither is a controlled variable. The value of the product moment correlation coefficient \(r\) for the data is 0.987 correct to 3 significant figures.
2. The speed of the car is converted to miles per hour and the time to minutes. State the value of \(r\) for the converted data.
3. State the value of Spearman's rank correlation coefficient \(r _ { s }\) for the data.
4. What information does \(r\) give about the data that is not given by \(r _ { s }\) ?