On the Data tab of the I-MR Chart dialog box, enter your data and set the length of the moving range.
In Variables, enter one column of measurement data.
Enter the number of observations that are used to calculate the moving range. By default, a length of 2 is used because consecutive values have the greatest chance of being alike. The length must be 100.
If the data are cyclical, consider using a moving range of a different length. For example, if you collect quarterly data, consider using a moving range of length 4 to ensure that one observation from each season is included in the calculation.