An Example of a Multiple Axis Graph.

1. It has been noted that when a multiple scale is used on an arithmetic chart, all scales must have a common zero line. When the data are chant; ed to index numbers, it is possible to arrange the curves on a multiple axis; that is, each curve fluctuates around its own base, or 100, and can be moved farther from or closer to other curves without distorting the facts presented.

2 The purpose of this arrangement is to facilitate comparisons of the time and amplitude changes in the curves.

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Chapter 38 FREQUENCY CHARTS

■ HE charts in this chapter present data showing frequenoy distribution. The most common bases of classification or arrangement are according to kind, size, location, or time of occurrence. Other terms that may be applied to this type of chart are histogram, distribution chart, and block diagram. When the curve in a frequency chart assumes the shape of a bell, it may be called a bell curve chart.

to

to

to

8 II 14 17 20 23 26 29 32 35

to to to to to to to to to end

II 14 17 20 23 26 29 32 35 mort Income in tt^ousonds of dollars

WPA Division of Social Rrscirrh. "L.Tndlortl and Tenant on ttif Cotton Plantation." IQJ6.

Distribution of Total Gross Income of 645 Cotton Plantations in the United States in 1934.

A frcqiit'ncy chart is a distribution accordinn to certain catcnorics. In this chart the cate- Horifs arc income groups. The first bar represents the number of cotton plantations in the United States with an income less than $2,000 a year, while the last bar represents the number of plantations with an income of $35,000 or more.