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

The histogram of cholesterol shows positive skewness. The superimposed Normal distribution curve extends below the lowest cholesterol represented in the histogram and does not extend far enough at the high cholesterol end of the histogram. The mode of the Normal distribution is at a higher cholesterol than the mode of the histogram.

The Normal plot has cholesterol on the vertical axis and Inverse Normal on the horizontal axis. The line of points curves upwards. The points are above the straight line of perfect Normal distribution for low cholesterol, below the line in the middle of the range of cholesterol, and above the line for high cholesterol.

Back to Clinical Biostatistics: Transformations.

This page maintained by Martin Bland.

Last updated: 3 August, 2006.