This is a scatter diagram, showing mean PEFR for the subject on the horizontal axis and the individual PEFR measurements minus the subject mean on the vertical axis. There is no sign of a relationship. The vertical spread of the points very similar all the way, with range about 70 litres per minute.
Back to Measurement in Health and Disease: Measurement error.
This page maintained by Martin Bland.
Last updated: 21 April, 2008.