The scatter diagram shows eight pairs of values of \(x\) and \(y\). A line of best fit has been drawn using the seven points that follow the trend. (a) Writ...

The line of best fit here was drawn using only the seven points that follow the trend, which is what makes the estimate in the last part dependable.

(a) Those points rise from bottom left to top right, so larger \(x\) goes with larger \(y\) and the correlation is positive [B1].

(b) The point that does not fit the trend lies well below the band formed by the others, at \((35,\,15)\) [B1]. Read the horizontal coordinate first, using the scale printed on the axis rather than counting squares.

(c) Go up from \(x=45\) to the line of best fit, then read across horizontally to the \(y\)-axis [M1]. This gives \(47\), with any answer from \(44\) to \(50\) accepted [A1].

The method mark is for the correct use of the line, so drawing the guide lines from the axis to the line and across is worth doing even if the final reading is slightly off. An estimate taken from a nearby plotted point instead of the line does not earn it.