Basics

In Six Sigma projects and the associated statistical evaluations, statements about process capabilities and critical process inputs are to be made based on the available data. For the selection of the right graphical and statistical tools, it must be clear ....

The normal distribution, also known as the Gaussian distribution, is the most commonly used statistical distribution. The deviations of the (measured) values of many scientific, economic and engineering processes from the mean value can often be described in a good approximation by the normal distribution.

Mean, median and modal are measures that describe the centre or position of the data.

Often the values are confused or the concrete calculation is not known.

The difference between the values is explained below.

Depending on the available data, the sigma level can be used to make statements about short-term or long-term capability!

The short-term capability covers a relatively short period of time and typically consists of ...

Process capability refers to how well a process or its result (output) matches the requirement (customer request). With the help of the process capability index .............

In practice, we check our measuring systems far too infrequently and this despite the fact that the usability of the measuring systems is often very poor. Even a newly calibrated measuring device can be unusable for the measurement for which it is used.

Why do we need to check the measurement systems?

Hypothesis tests are used to decide whether an influence or a change is significant or not based on samples. The core of the problem is that it is not known how far the sample deviates from the real process. Even representative samples have random scatter...