The point of interest in this chart is the net income or deficit of the various railroads.

Tlic number of miles of line were probably included to show that there is no evident relationship between the length of the railroad and profit or loss.

2. The dividing line between the two groups of bars in this chart is not a zero line with

plus and minus quantities to right and left, since miles are the quantity on one side and dollars the quantity on the other.

3. Thus the arrangement of the bars alone makes this a bilateral bar chart.

GRAPHIC PRESENTATION

Female

Percent 60 50 40 30 20 10

I 1 1 \ 1 r

Agriculture Forestry and Fishing

Extraction of Minerals

Manufacturing and Mechanical Industries

Transportation and Communication

Trade Public Service

Professional Service

Domestic ond Personal Service

Clericol Occupotions

Male

Percent 20 30 40 50 60

Relief 1934 Census 1930

WPA, Division of Social Rcsr.-irch, "Urban Workrrs on Rclirf." 1036.

Usual Occupation of Unemployed Workers on Relief in 1934 and Gainful Workers in 1930 in the United States.

The method of reading tfiis chart is as follows: according to the 1930 census about 42% of male gainful workers were in the manufacturing and mechanical industries. In 1934 about 52% of the men on relief designated manufacturing and mechanical industries as their former place of employment. This latter fact does not seem so startling in view of the first statement.

Chapter 17 AREA BAR CHARTS

THE BASIS of comparison in an area bar chart is the area of the bar rather than the length of the bar. Other terms appHed to this type of chart are, 100% square; 100% block.