Writing and Publishing Scientific Articles
8-14
Graphs
Graphs are figures that show relationships between data or trends in data. Following are best practices for some common types of graphs: line graphs, bar graphs, and pie graphs.
Line Graphs
Line graphs are very commonly used in scientific articles. Line graphs are 2-axis graphs that show the relationship between 2 quantitative variables. Line graphs depict trends, such as changes over time. They are usually designed with the dependent variable (the outcome variable of interest) on the vertical axis (y-axis) and the independent variable (the variable that is thought to influence the dependent variable) on the horizontal axis (x-axis). The axes are labeled with both the variable and the unit of measurement; on linear scales, tick marks representing equal intervals must be equally spaced. Axes and their labeling should not extend far beyond the data shown. The symbols used for the data points must be defined and easily distinguishable. Axis labels should be short and printed so that they are easily readable.
700
Protein-adequate Protein-deficient
600
Me
500
an
Bo
400
dy
300
Wei
ght
200
(g)
100
0
012345678910 Months
Figure 10. Mean body weights (± SEM) of weanling guinea pigs fed protein-adequate (n = 10) and protein-deficient diets (n = 10) for 10 months. The guinea pigs were weighed monthly. Body weights for the 2 groups were significantly different (P < 0.05, Student’s t test) beginning at month 2 and continuing until the end of the study. The legend here specifies the species studied, experimental groups, number of animals used, duration of study, statistical test and significance level, and other information. Here, the symbols used to distinguish results for the 2 groups are defined in the figure itself. In some figures, that information may be found in the legend.
Made with FlippingBook Digital Publishing Software