Defining Variables for Multiple Stream X-Bar and R Chart - Quick Tab

Select the Quick tab of the Defining Variables for Multiple Stream X-Bar and R Chart dialog box to access the options described here.

Element Name Description
Input is raw data (Compute means, etc.). Select this option button if the input data consist of raw measurements; for X-bar and R or S charts, the program will then compute the sample means and ranges or standard deviations from the data, and plot those statistics in the requested quality control charts.
Input is aggregated data (Data contains means, etc.). Select this option button if the input file already contains aggregated summary statistics, i.e., sample means and ranges or standard deviations. In this case, in the results dialog, various options for charts and other results tables that require access to the raw data will not be available. If for your QC application you are already storing the respective summary statistics in a database (which you are accessing via this module), then creating charts from aggregated data will be more efficient and may be faster.
Variables Click the Variables button to display a standard variable selection dialog box. The specific variable(s) that you need to select from this dialog depends on whether the input data for the analyses is raw data or aggregated data.
  • If the input data is raw data, you can select Variables with measurements, Variables with sample identifiers, and Variables with part identifiers (optional for short run charts).
  • If the input data is aggregated data (for an X-bar and R or S chart), you can select Variables with measurement Sample means, Sample ranges (for R charts; or Sample standard deviations for S charts), optionally with Sample sizes, and Part identifiers (optional for short run charts).
Constant sample size Select this check box if you are analyzing raw data and do not have a variable with sample identifiers. Specify the sample size for variable control charts by typing the number in the box or by adjusting the number with the microscrolls.
Minimum number of observations per sample Specify a minimum n per sample by typing it in or by adjusting the number with the microscrolls. Samples with fewer observations than the minimum specified will be ignored.