This is a scatter plot of residuals against predicted head circumference, as shown in Answer 4.
A graph with the horizontal axis labelled “Predicted head circumference (mm)” and numbered 540, 560, 580, 600. The vertical axis is labelled “Residual (mm)” and numbered -50, 0, 50, 100. Each student’s predicted head circumference and residual is shown as a point, represented by a little hollow diamond shape. The points form a roughly oval cloud with the highest density of points in the middle. When predicted head circumference is 550 mm, residuals range from about -40 to +50 mm. When predicted head circumference is 570 mm, residuals range from about -40 to +60 mm. When predicted head circumference is 590 mm, residuals range from about -50 to +60 mm.
There are a few outliers both with low and with high residuals at the high head circumference end, with one residual of 100 for a head circumference = 580 mm.
Apart from these outliers, there is nothing to suggest that residual is related to predicted head circumference.
Back to Exercise: Head circumference, sex and height.
This page maintained by Martin Bland.
Last updated: 20 March, 2007.