If the sample count is less than the total number of categories then dashes (---) are displayed instead of the values.
To test this, you can use the sample project located in the demo at location: \Quinn-Curtis\DotNet\QCSPCChart\Visual CSharp\examples\TimeAttributeControlCharts
Edit the NumberDefectivePartsControlChart.cs and change the line: int numsamplespersubgroup = 50; to int numsamplespersubgroup = 3;
After doing this, you will notice that values for the first 3 categories will be displayed, but the rest of the categories will show dashes.
A NP chart measures the number of parts non-conforming (i.e. the number of defective parts). It is not possible to have more defective parts than the actual number of parts sampled. That seems to be what your example is doing. Because of a common code shared with variable control charts, the number of processed categories is limited to lessor of the sample size compared to the specified number of categories.
Is this a real problem with an actual application or just something you noticed by randomly changing setup parameters in the graph? You can just turn off the category display if you want. Then is will just display the total number of defective parts.
A NP chart measures the number of parts non-conforming (i.e. the number of defective parts). It is not possible to have more defective parts than the actual number of parts sampled. That seems to be what your example is doing. Because of a common code shared with variable control charts, the number of processed categories is limited to lessor of the sample size compared to the specified number of categories.
Is this a real problem with an actual application or just something you noticed by randomly changing setup parameters in the graph? You can just turn off the category display if you want. Then is will just display the total number of defective parts.
this.EnableCategoryValues = false;
Yes this is a real problem. After noticing this problem with the charts I figured it would be better to see if I could recreate this problem using the demo code provided with the least amount of modifications to the code.
In our case, we have 19 attributes (categories) and the customer is taking 10 samples. Since the # of samples is only 10, categories 11-19 show dashes instead of the real values.
NP chart not displaying all categories
Posted - 03 Jul 2013 : 13:57:33
