IB skill practice

Interpret residual plots

Use residual size and sign to judge prediction error and model suitability.

Paper 1, Paper 2 5 marks Difficulty 5

Interpret residual plots - diagnostic reading

In an finance desk regression, an observed value is 58 and the fitted model predicts 55. Calculate the residual using observed minus predicted. Confirm the method before entering the value. Enter the requested value and choose the interpretation that matches the result.

Worked practice: result and interpretation

Calculate the requested result first, then choose the interpretation that follows from it.