This is a scatter diagram, showing the first F E V measurement for the subject on the horizontal axis and the second F E V measurement on the vertical axis. There is a strong positive relationship. There is an oval cloud of points with no increase in variability as F E V increases. There are a few outliers.
The graph is split vertically at first F E V = 1.5 litres. Points to the left of this vertical split are shown as red diamonds, points to the right of this vertical split are shown as blue squares.
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This page maintained by Martin Bland.
Last updated: 21 April, 2008.