Histogram of F E V with superimposed Normal distribution curve. The histogram is roughly symmetrical and the Normal curve fits it quite well. In the histogram, the lowest class is 2.5 to 3.0 litres, highest is 5.0 to 5.5 litres, modal class is 4.0 to 4.5 litres. The Normal curve has its mode about 4.2 and would reach the horizontal axis at about 2.0 and 6.3 litres.

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Last updated: 7 May, 2008.