Analysis Configuration: Run Tests Options

From an IQC Analysis Configuration in the tree view, under SPC Characteristics, expand any of the Characteristics and select Run Tests. Note. Whether the IQC Analysis Configuration has characteristics on which Quality Control analyses will be performed is dependent on whether the column in the Data Configuration on which the current Analysis Configuration is based has columns set to Target Types of Variable Characteristic, Attribute Characteristic, or Aggregate Attribute Characteristic.

Zones
Use the options in this group to set the size of the zones. For an in-depth discussion of Run Rules and their application, search for the Runs Tests help topic in the main STATISTICA Help.

C: From center to ± ____ * sigma. By default, Zone C is defined as the area between the center line and 1 times sigma.

B: From Zone C to ± ____ * sigma
By default, Zone B is defined as the area between 1 and 2 times sigma.
A. From Zone B to ± ____ * sigma.
By default, Zone A is defined as the area between 2 and 3 times sigma above and below the center line.

Number of points (samples) in a row (runs).

On the same side of center line (Zone C or beyond)
The default value is 9. If this test is positive (i.e., if this pattern is detected), then the process average has probably changed. Note that it is assumed that the distribution of the respective quality characteristic in the plot is symmetrical around the mean. This is, for example, not the case for R charts, S charts, or most attribute charts. However, this is still a useful test to alert the quality control engineer to potential shifts in the process. For example, successive samples with less-than-average variability may be worth investigating since they may provide hints on how to decrease the variation in the process.
Increasing or decreasing (trend)
The default value is 6. This test signals a drift in the process average. Often, such drift can be the result of tool wear, deteriorating maintenance, improvement in skill, etc. (Nelson, 1985).
Alternating up and down
The default value is 14. If this test is positive, it indicates that two systematically alternating causes are producing different results. For example, one may be using two alternating suppliers or monitoring the quality for two different (alternating) shifts.
In Zone A or beyond
The default value is 2 out of 3. This test provides an "early warning" of a process shift. Note that the probability of a false positive (test is positive but process is in control) for this test in X-bar charts is approximately 2%.
In Zone B or beyond
The default value is 4 out of 5. Just as in the previous test, this test may be considered to be an "early warning indicator" of a potential process shift. The false-positive error rate for this test is also about 2%.
In Zone C (above and below center line)
The default value is 15. This test indicates a smaller variability than is expected (based on the current control limits).
Beyond Zone C (above and below center line)
The default value is 8. This test indicates that different samples are affected by different factors, resulting in a bimodal distribution of means. This may happen, for example, if different samples in an X-bar chart were produced by one of two different machines, where one produces above average parts and the other below average parts.
Perform test on overlapping ranges
Select this check box to perform the runs tests selected above on overlapping ranges.
Compute tests for R/S (variability) charts
Select this check box to perform the runs tests selected above on R/S variability charts.
Restore default
Click this button to reset all options in the Run Tests properties page to the default settings.