Graph description: Figure 7. Data of Figure 6 after logarithmic transformation.

This is a scatter diagram, showing average log VCF by long and short axes on the horizontal axis and the difference in log VCF, long minus short, on the vertical axis. The horizontal scale is labeled minus 0.4, minus 0.2, 0, 0.2, 0.4. The vertical scale is labeled minus 0.2, minus 0.1, 0, 0.1, and 0.2. The two scales are not equal.

There are three horizontal lines on the graph, approximately through minus 0.1, 0, and plus 0.1. The lowest line is labeled mean minus 2 S D, the middle line is labeled mean, the highest line is labeled mean plus 2 S D.

The points plotted on the graph form a cloud with with centre at about 0.1 horizontally and 0 vertically. This cloud extends horizontally from about minus 0.1 to plus 2.5 and vertically from minus 0.1 to plus 0.1.

There are five points outside the top and bottom lines, at about average = 0.08, difference = minus 0.16, at about average = 0.1, difference = plus 0.12, at about average = 0.14, difference = minus 0.12, at about average = 0.21, difference = minus 0.12, and at about average = 0.23, difference = plus 0.15. In addition, there are two outliers for the average, at about average = minus 0.25, difference = plus 0.06 and at about average = minus 0.36, difference = minus 0.03.

These outliers give the cloud of points a rather triangular appearance, but not nearly so pronounced as in Figure 6.

Back to Measurement in Health and Disease: Assessing Agreement Between Methods Of Clinical Measurement.

This page maintained by Martin Bland.
Last updated: 29 April, 2008.