5 An ornithologist is investigating the link between the wing length and the mass of small birds, in order to try to predict the mass from the wing length without having to weigh birds. The ornithologist takes a random sample of 9 birds and measures their wing lengths \(w \mathrm {~mm}\) and their masses \(m g\). The spreadsheet below shows the data, together with a scatter diagram which illustrates the data.
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- Find the equation of the regression line of \(m\) on \(w\), giving the coefficients correct to \(\mathbf { 3 }\) significant figures.
- Use the equation which you found in part (a) to estimate the mass for each of the following wing lengths.
- 99 mm
- 110 mm
- Comment on the reliability of your estimates.
- The equation of the regression line of \(w\) on \(m\) is \(w = 0.473 m + 87.5\). A friend of the ornithologist suggests that this equation could also be used to estimate the masses of birds from their wing lengths.
Comment on this suggestion.