Question

List the common types of statistical measures that might be used in Statistical Methods in Quality Management to track the central tendency and spread of the output from a process. For each statistical measure describe a situation when you would choose to apply the specific measurement technique.

Answer 1

Statical measures that are used in quality management to track the central tendency and spread of output from a process are process optimisation, process capability index, screening experiment, regression coefficient.

Optimization technique used to adjusting a process so it helps in optimize some specified parameter sets without violating any constraint. It maximizes function to find an optimum set of conditions. This technique applied when optimum quality control required.

In process capability index is a statistical method of process capability. The ability of the process to produce output with specified limits. It is applied when the sample size greater than 30 with n>90 and sampling time sufficient to see the total range of process variation.

In screening experiment technique used to identify factors for further examination.

Screening designs to screen out some factors for additional analysis in subsequently refining the quality process. No runs large enough to detect significant effects with 95% confidence, increase factors range to detect and maximizing probability to find out the effects. It is applied when finding out and eliminate factors that are affecting the quality management.

The regression coefficient technique establishing a relationship between the input and output variables and their optimization and control. It is applied when input and output to be measure. The sample size should be large enough to detect with a 95% coefficient.