Types of Graph And when to use them!

Line Graph

Line Graph Used to show trends Variable plotted on X (bottom) musts be continuous Common type is “time series” where X = time CANNOT be used to graph data where X is discrete

Scatterplot

Scatterplot Used to show relationships between variables X variable must be continuous If one variable is believed to cause or explain changes in the other, that variable is plotted on the X

Bar Graph

Bar Graph Used to compare amounts or frequencies in data that represents different categories (discrete data sets) Categorical data set is plotted on X, quantitative (continuous) on the Y Often used incorrectly to graph data with continuous X variables

Histogram

Histogram Used when discrete X is converted to categories (“bins”) Y represents frequency of data within each “bin”

Pie Chart

Pie Chart Used for same kind of data as bar chart Each slice = data category Slice size shows relative proportion of observations within each category

Summary: Types of Graph Graph type Use Line graph Connects dots with lines Used for continuous X data Show patterns or trends If time = X, time-series graph Scatterplot Display/assess relationship between variables Bar graph Used to show patterns Should only be used when X data are categorical

Graph type Description Histogram Similar to bar graph, but used when continuous X data are converted to categories Pie chart Compares small number of categories. Works best if values are very different. If similar, should label pie segments with actual values