A histogram of duration of venous ulcer : a graph where the horizontal axis is labeled Duration of ulcer (months) and numbered 0, 12, 24, 36, 48, 60, 72 and the vertical axis is labeled frequency and numbered 0, 50, 100, 150, 200.

There are vertical bars with bases 0 to 2, 2 to 4, 4 to 6, 6 to 8, and so on, with heights 127, 63, 42, 17, 18, 18, 3, 9, 6, 4, 14, 2, 4, 4, 2, 6, 1, 5, 0, 3, 5, 9, 6, 0, 1, 5, 1, 0, 1, 0, 1, 0, 2, 0, 2, 0, 1, 0, 0, and 1.

The mean minus two standard deviations is shown at duration = -19. The mean minus one standard deviation is shown at duration = -5. The mean is shown at duration = 9. The mean plus one standard deviation is shown at duration = 23. The mean plus two standard deviations is shown at duration = 37.

The mean minus two standard deviations and the mean minus one standard deviation each appear below zero.

Back to Clinical Biostatistics: Data, frequencies, and distributions.

This page maintained by Martin Bland.

Last updated: 2 August, 2006.