# Graph description: Figure 6. Histograms showing the cotinine data on a natural and a logarithmic scale

This is a graph with two panels, each showing a histogram.

The first histogram shows the first cotinine measurement in millimoles per litre on the horizontal axis, with scale labeled 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. Additional scale points are marked at 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9. The vertical scale shows Frequency and is labeled at 0, 20, 40, 60, 80. The vertical bars of the histogram are width 0.5 and have heights about 72, 34, 12, 12, 5, 6, 5, 6, 5, 4, 0, 0, 0, 1, 1, 2, 0, 0, 1, 1.

The second histogram shows the first cotinine measurement in millimoles per litre on the horizontal axis, with a logarithimc scale. The scale is labeled 0.05, 0.1, 0.5, 1, 5, 10. Additional scale points are marked at 0.6, 0.7, 0.8, 0.9, 2, 3, 4, 6, 7, 8, 9. Because this is a logarithmic scale, the intervals between scale points get smaller from 0.05 to 1 and then the interval from 1 to 2 is wider again, as wide as the interval between 0.1 and 0.2, The intervals then get progressively smaller from 1 to 10. The distances between 0.05 and 5, between 0.1 and 1, and between 1 and 10, are all the same. The vertical scale shows Frequency and is labeled at 0, 10, 20, 30, 40. The vertical bars of the histogram are of constant width and there are 12 of them between scale points 0.05 and 10. The bars and have heights about 12, 7, 0, 15, 38, 21, 13, 12, 13, 21, 5, 6.

The first 7 bars of the second histogram span the horizontal distance from 0.05 to 1, while the first first two bars of the first histogram span the distance from 0 to 1.