Interval plots are used to display the mean of a group of data and an interval bar around the mean. The intervals can be either standard error bars or confidence intervals.
Here, we will use the Camshaft2.MTW
worksheet from the Minitab example data folder. The data shows a recorded length of camshaft from the two suppliers. The interval plot is used to display the mean and confidence interval of the mean for each supplier.
The following instructions will create an interval plot showing 95 percent confidence intervals around the mean value.
Go to the File menu and select Open Worksheet….
Click on the button labeled Look in Minitab Sample Data folder.
Open the
Camshaft2.MTW
worksheet.In the Graph menu, go to Interval Plot….
Select the With Groups chart under One Y.
Enter
Length
into the Graph variables: section.Enter
Supplier
into the Categorical variables for grouping (1-4, outermost first): section and then click on OK.