11 terms

Frequency Polygon

Uses line segments connected to points located directly above class midpoint values.

Relative Frequency Polygon

Uses relative frequencies (proportions or percentages) for the vertical scale. When trying to compare two data sets, it is often very helpful to graph two relative frequency polygons on the same axes.

Ogive

A line graph that depicts cumulative frequencies. Uses class boundaries along the horizontal scale, and cumulative frequencies along the vertical scale.

Dotplot

Consists of a graph in which each data value is plotted as a point (or dot) along a scale of values. Dots representing equal values are stacked.

Stemplot (or Stem-and Leaf plot)

Represents quantitative data by separating each value into two parts: the stem (such as the leftmost digit) and the leaf (such as the rightmost digit).

Bar Graph

Uses bars of equal width to show frequencies of categories of qualitative data. The vertical scale represents frequencies or relative frequencies. The horizontal scale identifies the different categories of qualitative data. The bars may or may not be separated by small gaps.

Multiple Bar Graph

Has two or more sets of bars, and is used to compare two or more data sets.

Pareto Chart

A bar graph for qualitative data, with the added stipulation that the bars are arranged in descending order according to frequencies. The vertical scale in a Pareto chart represents frequencies or relative frequencies. The horizontal scale identifies the different categories of qualitative data. The bars decrease in height form left to right.

Pie Chart

A graph that depicts qualitative data as slices of a circle, in which the size of each slice is proportional to the frequency count for the category.

Scatterplots (or Scatter Diagram)

A plot of paired (x, y) quantitative data with a horizontal x-axis and a vertical y-axis. The horizontal axis is used for the first (x) variable, and the vertical axis is used for the second variable. The pattern of the plotted points is often helpful in determining whether there is a relationship between the two variables (example pg. 64).

Time - Series Graph

A graph of _______ data, which are quantitative data that have been collected at different points in time.