Back to Assess fit by analyzing residuals — Problem 4 · Task Set 7

Exercises: Assess Fit by Analyzing Residuals

Work through each section in order. A residual is observed minus
predicted: positive when the data point is ABOVE the model, negative
when below. Keep the sign. When reading a residual plot, remember the
key idea: random scatter around zero means a GOOD fit, while a clear
pattern (a curve or a fan) means the model is wrong.

Grade 10·20 problems·~35 min·Common Core Math - HS Statistics and Probability·standard·hss-id-b-6b

Work through problems with immediate feedback

Fluency Practice

Compute residuals and read residual plots.

$A residual plot with points scattered randomly above and below a dashed horizontal zero line, showing no pattern.$

The residual plot below shows residuals scattered randomly around the zero line with no clear pattern. What does this say about the fit of the model?

The model fits well; random scatter around zero means only noise is left over.

The model is poor, because the residuals are not all exactly zero.

The model is poor, because some residuals are negative.

You cannot tell anything from a residual plot.