Minitab provides a flexible suite of graphs on the Graph menu to support a variety of analysis needs. Many customization options are available when you create a graph and many more are available after you create it.
In addition to the graphs available from the Graph menu, Minitab offers analysis-specific graphs on the Stat menu, such as control charts. Minitab also has built-in graphs as part of many statistical analyses.
Use a scatterplot to assess the relationship between two variables. The values of the two variables serve as the x- and y-coordinates for plotting each observation. In Minitab, choose
.Use a matrix plot to assess the relationships among several pairs of variables at once. A matrix plot is an array of individual scatterplots. In Minitab, choose
.Use a histogram to evaluate the shape and central tendency of your data, and to assess whether or not your data follow a specific distribution such as the normal distribution. In Minitab, choose
.Bars represent the number of observations falling within consecutive intervals or bins. Because each bar represents many observations, a histogram is most useful when you have a large amount of data.
Use a dotplot to evaluate the shape and central tendency of your data. Like a histogram, a dotplot is divided into bins. However, a dotplot can be more useful than a histogram when you have a small amount of data because each dot represents a single observation, or a small number of observations. In Minitab, choose
.Dotplots are also useful for comparing groups of data.
Minitab plots the value of each observation against its estimated cumulative probability. The scales are transformed, so that the fitted distribution forms a straight line.
Minitab plots a stepped function representing the cumulative distribution observed in the sample and the fitted cumulative distribution based on parameters estimated from the sample.
Use a boxplot to assess and compare distribution characteristics such as median, range, and symmetry, and to identify outliers. In Minitab, choose
.Use a boxplot to assess and compare sample distribution characteristics and to look for outliers. In Minitab, choose
.Use an interval plot to assess and compare means and confidence intervals. The confidence intervals help you assess the differences between group means in relation to within-group variance. In Minitab, choose
.Use an individual value plot to assess and compare individual data points. In Minitab, choose
.This graph plots each data point for each group so that you can see outliers and the shape of the distribution.
Use a line plot to compare response patterns for two or more groups. Minitab can calculate summary statistics from raw data or you can plot summary values from a table in your worksheet. In Minitab, choose
.Use a bar chart to compare a summary statistic, such as the mean, for groups of data. Minitab can calculate summary statistics from raw data, or you can plot summary values from a table in your worksheet. In Minitab, choose
.Minitab provides several tools you can use to view patterns in data over time. For example, you can use these tools to examine monthly sales for your company.
Use a time series plot if your data were collected in equally-spaced time intervals and are in chronological order in the worksheet. In Minitab, choose
.Minitab plots observations on the y-axis against equally-spaced time intervals on the x-axis.
Use an area graph to see how the composition of the sum changes over time. In Minitab, choose
.Minitab plots a series of stacked variables on the y-axis against equally spaced time intervals on the x-axis. Each line on the graph is the cumulative sum.
Use a scatterplot with a connect line if your data were collected at irregular intervals or are not in chronological order in the worksheet. You must provide a time variable from the worksheet. In Minitab, choose
.This graph plots observations on the y-axis against the time on the x-axis.
Use these graphs to view three variables in a single plot. For example, you can assess how temperature and humidity affect drying times for paint.
Use a 3D surface plot to create a three-dimensional surface based on the x-, y-, and z-variables. In Minitab, choose
.A 3D surface plot is similar to a 3D scatterplot except that Minitab displays a continuous surface (surface plot) or a grid (wireframe plot) of z-values instead of individual data points.
Built-in graphs are the graphs that are displayed as part of many Minitab statistical analyses, so that you can view the data or verify statistical assumptions. When you perform an analysis, you can choose to produce a built-in graph as part of the output.
For example, when performing a regression analysis, you can choose to draw one or more of the following graphs: histogram of residuals, normal probability plot of residuals, residuals vs fits, and residuals vs order; or choose four-in-one, which is all the graphs in a single Graph window. These graphs provide an easy visual verification of whether or not your model meets the assumptions of the analysis.