Enter your data for U Chart Diagnostic

Stat > Control Charts > Attributes Charts > U Chart Diagnostic

Enter the process data and subgroup size

  1. In Variables, enter the column that contains the process data. Each row contains the number of defects for one subgroup. If you enter more than one column, Minitab creates a separate U chart diagnostic test for each column.
  2. In Subgroup sizes, do one of the following:
    • If all subgroups are the same size, enter the size (for example, 55).
    • Enter a column that contains the size of each subgroup.
In this worksheet, the Irregularities column contains the number of defects, such as tears and pulls, that were found in each subgroup. The Yards Sampled column indicates the size of the subgroup. For example, row 1 indicates that 10 irregularities were found in 120 yards of fabric.
C1 C2
Irregularities Yards Sampled
10 120
8 110
7 110
7 115

Specify subgroups to estimate parameters

If some subgroups have erratic data because of special causes that you have already corrected, you can omit these subgroups from the calculations to avoid incorrect parameter estimates.

  1. From the drop-down list, specify whether you want to list the subgroups to omit or the subgroups to include.
    • To list the subgroups to omit, select Omit the following subgroups when estimating parameters (eg, 3 12:15).
    • To list the subgroups to include, select Use the following subgroups when estimating parameters (eg, 3 12:15).
  2. List the subgroups. Use a colon to indicate a range of subgroups. Leave a space between each subgroup or range of subgroups.
    For example, to specify rows 4, 7, 11, 12, 13, and 14, enter 4 7 11:14.