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Electronics, October. 1938.

Number of Radio Sets and Radio Receiving Tubes Built In the United States from 1922 to 1937

1. The curves in these charts illustrate the plotting of a curve on a grid.

2. The points are plotted on the vertical rulings and a connecting line is drawn through

each point.

3. In plotting a curve, there are two variables, the independent and the dependent. In

these curves, the time scale indicates the independent variable, and the amount scale the dependent variable.

GRAPHIC PRESENTATION

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A. Sulphuric Acid Prices in the United States From 1924 to 1938.

Often a curve chart takes the appearance of a stair chart when prices which remain stable over a long period of time are presented. This should not be confused with such charts as 1358.

Standard Statistics. Inc.. N. Y. C, "Standard Trade and Securities." March 4, 1Q38.

SCALE .6

Abstracts from Time Series Charts. A Manual of Design and Construction, 1938, prepared by Committee on Standards for Graphic Presentation, under procedure of American Standards Association, with The American Society of Mechanical Engineers as sponsor body.

TIME-SERIES LINE CHARTS

The "time-series line chart" is the type in which values of a time series are plotted on a coordinate surface ond the points joined together successively to form a continuous line or "curve." The line chart has a wide range of application and in most cases is relatively easy to construct and maintain.