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Unformatted text preview: Table 1.4 Graphs
The results of an experiment usually are presented graphically, showing the relationships among
the independent and dependent variable(s). A graph provides a summary of the results and allows
you to see relationships in the data that may not have been apparent in a table. Your graph should
be accurately and clearly constructed, easily interpreted, and well annotated.
The following guidelines will help you to construct such a graph.
• Use graph paper and a ruler to plot the values accurately. If using a database program, you
should first sketch your axes and data points before constructing the figure on the computer. • The independent variable is graphed on the x axis (horizontal axis, or abscissa), and the
dependent variable, on the axis (vertical axis, or ordinate). • The numerical range for each axis should be appropriate for the data being plotted. Generally,
begin both axes of the graph at zero (the extreme left corner). Then choose your intervals and
range to maximize the use of the graph space. Choose intervals that are logically spaced and
therefore will allow easy interpretation of the graph, for example, intervals of 5s or 10s. To
avoid generating graphs with wasted space, you may signify unused graph space by two
perpendicular tic marks between the zero and your lowest number on one or both axes. • Label the axes to indicate the variable and the units of measurement. Include a legend if colors
or shading is used to indicate different aspects of the experiment. • Choose the type of graph that best presents your data. Line graphs and bar graphs are most
frequently used. The choice of graph type depends on the nature of the variable being
graphed. 16 Exercise 1.B. Scientific Investigation: Experimental Design Applied • Compose title for your figure, and write it below your graph. Graphs, diagrams, drawings, and
photographs are all called figures and should be numbered consecutively throughout a lab
report or scientific paper. Each figure is giv...
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