Displaying small counts

When the range of values in a discrete data set is small, a histogram can be drawn with class width 1 without appearing too jagged. These classes are centred on the possible values in the data set (i.e. 1, 2, 3, etc).

Such a histogram can be improved by narrowing the rectangles so that they do not touch, since this emphasises the discrete nature of the data. The resulting display is called a bar chart of the data.

For discrete data, bar charts are preferable to histograms, provided this does not result in too many classes.

Hurricanes in the North Atlantic

The table below shows the numbers of hurricanes in the North Atlantic each year between 1910 and 2009.

Decade Year
Beginning 0 1 2 3 4 5 6 7 8 9
1910
1920
1930
1940
1950
1960
1970
1980
1990
2000
3
4
2
4
11
4
5
9
8
8
3
4
2
4
8
8
6
7
4
9
4
2
6
4
6
3
3
2
4
4
3
3
9
5
6
7
4
3
4
7
0
5
6
7
6
6
4
5
3
9
4
1
5
5
9
4
6
7
11
15
11
8
7
3
4
7
6
4
9
5
2
4
3
5
3
6
5
3
3
5
3
4
3
6
7
5
5
5
10
8
1
3
3
7
7
12
5
7
8
3

The diagram below shows a histogram of the data.

Use the slider to change the histogram into a bar chart — the best display of the data.