Question

Please TYPE your answer and please give the correct answer. Thank you!

If a process is in a state of statistical control, does it necessarily follow that all or nearly all of the units produced by the process will be within the specification limits? Also, does it necessarily follow that all or nearly all of the units produced by the process will be within the control limits? Be sure to explain your reasoning, and note which type of control limits you are considering when answering the second part of this question.

Answer 1

A process is in a state of statistical control if the production process is stabilized: Only common causes of variation remain. All special causes of variation have been removed. In the Control chart: all data points within control limits and no non random pattern of variation.

Yes, If a process is in a state of statistical control, it necessarily follows that all or nearly all of the units of product produced will be within the specification limits.

Relationship between control chart and statistical hypothesis testing:

Control chart detects a shift in the process and detecting trends. Statistical hypothesis testing is an assertion about accepting a null hypothesis as against alternative hypothesis which yields the probability that sample point falls in the critical region of the test.

Control Chart is a pre-requisite for Statistical Hypothesis Testing.

control chart varifies the assumption that a process is stable, which is required to produce a valid capability analysis.