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Chapter 34 COMPARISONS WITH TWO CURVES

HE types of curve charts covered in this chapter are simple comparisons of two curves, cumulative curves, causal relationships and high-low curves.

REFERENCES

Arkin, Herbert and Raymond R. Colton, Graphs: How to Make and Use Them, Harper & Brothers, New York City, 1937.

Croxton, Frederick E., and Dudley J. Cowden, Applied General Statistics, Prentice Hall Inc., New York City, 1939.

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National Educational Association. "Rcsfarch Bulletin, " May 1938.

SCALE .9

Trends in Teachers Salaries and Wages of Unskilled Labor in the United States fronn 1 900 to 1937.

1. When more than one curve is put on a grid, it is necesary to make some differentiation

between the curves. A dotted line is one solution.

2. The grid of a chart may be omitted to great advantage in some cases. Since the

omission often hinders the reading of the chart, the practice should not be encouraged.

GRAPHIC PRESENTATION

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