The moving range methodology allows For a reasonable estimate ofσand process capability for both variable and attribute processes. It uses individual measurements or defect rates over a representative...

There are four different methods for determining the standard deviation σ of the population for process capability studies:1. Total overall variation. All data is collected into one large group and tr...

The following procedures are recommended when time and resources are not gating items. It is ideally suited for large-volume manufacturing, where the parts cost is low £ind the ease of collecting data...

Process capability is the analysis of a process to determine its quality. A single or several quality characteristics are selected, some of which might be variable or attribute. For variable character...

The statistical relationships of the sample and population averages have been discussed in previous sections. There is a similar distribution for the sample variability s2, which can be used to learn...

Engineers have found the use of the confidence percentage discussed in the last section for estimating the average or average rather unfamiliar. They are more comfortable with the concept of the confi...

An engineer uses 100 samples to check the average noise output of amplifiers (in Db) produced in the production line. If it is known that the line is normally distributed with standard deviation of th...

The previous section has introduced some statistical terms that are not widely used by engineers but are very familiar to statisticians. This section is a review of some of the statistical terms and p...