Quality Control Charts Startup Panel - Attributes Tab

Select the Attribute tab of the Quality Control Charts Startup Panel to access the options described here.

C chart for attributes. Click the C chart for attributes option to select this analysis. This analysis produces a C chart for attributes. In this chart, we plot the number of defectives and it is constructed based on the Poisson distribution, which is also referred to as the distribution of rare events.

U chart for attributes. Click the U chart for attributes option to select this analysis. This analysis produces a U chart for attributes. In this chart we plot the rate of defectives, that is, the number of defectives divided by the number of units inspected. Like the C chart, it is based on the Poisson distribution, but unlike the C chart, this chart does not require a constant number of units, and it can be used, for example, when the batches (samples) are of different sizes.

Np chart for attributes. Click the Np chart for attributes option to select this analysis. This analysis produces an Np chart for attributes. In this chart, we plot the number of defectives (per batch, per day, per machine) as in the C chart, but it is based on the binomial distribution.

P chart for attributes. Click the P chart for attributes option to select this analysis. This analysis produces a P chart for attributes. In this chart, we plot the percent of defectives (per batch, per day, per machine, etc.) as in the U chart. However, the control limits in this chart are based on the binomial distribution (of proportions).

Pareto Chart Analysis. Click the Pareto Chart Analysis option to select this analysis. This analysis produces a Pareto chart. This option allows the user to plot a histogram by category, where the bars in the histogram are sorted in descending order. Such plots allow for the easy identification of the primary sources (categories) of quality problems.

See also, Common Types of Charts, Control Charts for Variables vs. Charts for Attributes, Quality Control Index, and Technology of the STATISTICA Quality Control Charts Module (Technical Note).