Percentile lines are specialized reference lines available only with probability plots and empirical CDF plots. A percentile line has two segments that intersect at the fitted distribution line. One segment is drawn to intersect the data scale and the other is drawn to intersect the other scale on the graph. This other scale can be a percent scale, a probability scale, or a score scale, depending on the option you have selected.
Percentile lines are often used for evaluations of test scores. For example, if you want to know the test score for the 95th percentile, you can add a percentile line at 95 percent. Minitab calculates the corresponding data value. Conversely, if you add a percentile line at the data value, Minitab calculates the corresponding percent.
An employee ranking at the 95th percentile achieved a test score of 31.64. In other words, 95% of the employees had a score of 31.64 or less.
A test score of 27 is slightly higher than the 70th percentile. Slightly more than 70% of the employees had a score of 27 or less.
You can add percentile lines when you create probability plots and empirical CDF plots.
You can add percentile lines to probability plots and empirical CDF plots.
You can edit a percentile lines color, size, line type, and label.
By default, a percentile line includes a label on the x-axis and a label on the y-axis. The first time you click one of the labels, both labels are selected. Click the same label again to select only that label. (For more information, go to Select groups and single items on a graph.)
Click and drag to move a label.