Two graphs, a histogram with a superimposed Normal curve and a Normal plot.

The histogram has "Sodium (mmol/L)" on the horizontal axis numbered 100, 140 and 180. The vertical axis is labeled "Frequency" and numbered 0, 20, 40, 60, 80, and 100.

The histogram is roughly symmetrical with mode at Sodium = 120 to 140, frequency = 90. The only bars with frequencies above 10 are between 125 and 150. There are bars with non-zero frequency between 110 and 170. The Normal distribution curve fits the central part of the distribution quite well, though it is not high enough at the mode. The tails of the Normal distribution do not reach into either tail of the histogram.

The Normal plot has Bloood sodium on the vertical axis and Inverse Normal on the horizontal axis. The line of points is not close to the straight line of perfect Normal distribution. The line of points starts below the straight line of perfect Normal distribution, then rises above it, then falls below it and finally rises above it.

Back to Clinical Biostatistics: Transformations.

This page maintained by Martin Bland.

Last updated: 8 August, 2006.