This plot of a difference from baseline simulation shows two scatter plots side by side. Each shows 30 points.
The lefthand graph shows the measurement after against the measurement before (baseline) and the line of equality. There is a rather weak positive relationship (r = 0.54).
The righthand graph shows the difference, after minus before, against before (baseline) and a regression line. There is a rather weak negative relationship (r = -0.23).
We can see that subjects with low baseline values tend to have high (positive) differences and that subjects with high baseline values tend to have low (negative) differences.
Back to Regression towards the mean.
This page maintained by Martin Bland.
Last updated: 19 January, 2004.