Which graphs are included in Minitab?

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.

Scatterplot

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 Graph > Scatterplot.

Binned scatterplot

Use a binned scatterplot to investigate the relationship between a pair of continuous variables when the data set contains many observations. In Minitab, choose Graph > Binned Scatterplot.

Matrix plot

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 Graph > Matrix Plot.

Bubble plot

Use a bubble plot to explore the relationships among three variables on a single plot. Like a scatterplot, a bubble plot plots a y-variable versus an x-variable. However, the symbols (also called bubbles) on the bubble plot vary in size. The area of each bubble represents the value of a third variable. In Minitab, choose Graph > Bubble Plot.

Marginal plot

Use a marginal plot to assess the distributions of two variables as well as the relationship between them. A marginal plot is a scatterplot with histograms, boxplots, or dotplots in the margins. In Minitab, choose Graph > Marginal Plot.

Histogram

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 Graph > Histogram.

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.

Dotplot

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 Graph > Dotplot.

Dotplots are also useful for comparing groups of data.

Stem-and-leaf

Use a stem-and-leaf plot to display the actual data values in a binned format. Though similar to a dotplot, a stem-and-leaf plot is turned on its side. A stem-and-leaf plot does the following:

• Uses the leading digits of the sample values to determine the bins (for example, one bin may have values between 0 and 9, another bin may have values between 10 and 19, and so on).
• Displays digits from the individual values instead of dots, and each of these digits represents a single observation.

In Minitab, choose Graph > Stem-and-Leaf.

Probability plot

Use a probability plot to do the following:

• Determine how well your data follow a specific distribution. The degree of fit is indicated by the degree to which the data points follow the fitted line.
• Obtain parameter estimates and estimated population percentiles.
• Compare sample distributions.

In Minitab, choose Graph > Probability Plot.

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.

Empirical CDF

Use an empirical CDF (cumulative distribution function) graph to do the following:

• Determine how well your data follow a specific distribution. A good fit is indicated when the stepped function follows the fitted line fairly closely.
• Obtain parameter estimates and estimated population percentiles.
• Compare sample distributions.

In Minitab, choose Graph > Empirical CDF.

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.

Probability distribution plot

Use a probability distribution plot to do the following:

• View the shape of a distribution.
• Understand how distribution parameters affect the distribution shape.
• Teach the concepts of confidence intervals and hypothesis testing.
• Determine critical values and p-values.

In Minitab, choose Graph > Probability Distribution Plot.

Boxplot

Use a boxplot to assess and compare distribution characteristics such as median, range, and symmetry, and to identify outliers. In Minitab, choose Graph > Boxplot.

Boxplot

Use a boxplot to assess and compare sample distribution characteristics and to look for outliers. In Minitab, choose Graph > Boxplot.

Interval plot

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 Graph > Interval Plot.

Individual value plot

Use an individual value plot to assess and compare individual data points. In Minitab, choose Graph > Individual Value Plot.

This graph plots each data point for each group so that you can see outliers and the shape of the distribution.

Line plot

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 Graph > Line Plot.

Parallel coordinates plot

Use a parallel coordinates plot to visually compare many series or groups of series on parallel coordinates across multiple variables. In Minitab, choose Graph > Parallel Coordinates Plot.

Bar chart

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 Graph > Bar Chart.

Pie chart

Use a pie chart to assess the contributions of each group relative to the whole. Minitab produces a pie chart from a table of summary values in your worksheet. In Minitab, choose Graph > Pie Chart.

Bar chart

Use a bar chart to compare the distribution of counts for up to four categorical variables. Data can be raw (each row in a column represents one observation) or in a frequency table (category names are in one or more columns and summary data are in another column). In Minitab, choose Graph > Bar Chart.

Pie chart

Use a pie chart to compare the proportion of each data value relative to the whole. Data can be raw (each row in a column represents one observation) or in a frequency table (category names are in one column and summary data are in another column). In Minitab, choose Graph > Pie Chart.

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.

Time series plot

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 Graph > Time Series Plot.

Minitab plots observations on the y-axis against equally-spaced time intervals on the x-axis.

Area graph

Use an area graph to see how the composition of the sum changes over time. In Minitab, choose Graph > Area Graph.

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.

Scatterplot with a connect line

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 Graph > Scatterplot > With Connect Line.

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.

Contour plot

Use a contour plot to map measurement values as a function of two other variables. In a contour plot, similar z-values are represented on the x-y plane by contour lines and colored bands. In Minitab, choose Graph > Contour Plot.

3D scatterplot

Use a 3D scatterplot to plot individual observations in three dimensions defined by the x-, y-, and z-variables. In Minitab, choose Graph > 3D Scatterplot.

3D surface plot

Use a 3D surface plot to create a three-dimensional surface based on the x-, y-, and z-variables. In Minitab, choose Graph > 3D Surface Plot.

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.

Bubble plot

Use a bubble plot to explore the relationships among three variables on a single plot. Like a scatterplot, a bubble plot plots a y-variable versus an x-variable. However, the symbols (also called bubbles) on the bubble plot vary in size. The area of each bubble represents the value of a third variable. In Minitab, choose Graph > Bubble Plot.

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 together in a single graph layout. These graphs provide an easy visual verification of whether or not your model meets the assumptions of the analysis.