When you perform a hypothesis test in Minitab, you can choose to display an individual value plot, a boxplot, and a histogram with your results. These and other graphs can help you summarize your results and more fully interpret the statistical results of a hypothesis test.
The scales used for a graph can dramatically affect how the results look. Therefore, when possible, use the calculated numeric results in the output to confirm what the graphs show.
You can use a graph to compare the sample statistic to the population parameter and illustrate the results of the hypothesis test. The following individual value plot illustrates the difference between the means of two samples, A and B.
You can use a graph to show the center of the data, which is the value or range of values that most of the data are near, such as the mean and median.
A boxplot cannot show a multi-modal distribution because there are two centers in the data.
Use graphs to show the show the range of the data and to see how far the data are from their center. If the data have a large spread, their variability may make the estimate of the central value less precise.
Histograms, boxplots, and individual value plots can help you easily see the spread in your data. To evaluate the spread more, boxplots display quartiles that let you easily estimate the interquartile ranges.
You can also use graphs to explore data and assess the validity of statistical assumptions for the test.