Comparison of robust estimators of standard deviation in normal distributions within the context of quality control

Pitman criterion is used in simulation to determine the "closer" estimator of the standard deviation among selected choices. The initial simulation utilizes a standard normal distribution from which samples are taken of specific sizes. Popular and commonly used estimators of standard deviation are compared with the known population standard deviation in this study. Closeness criterion is calculated for each comparison and sample size. A secondary simulation applies the findings to variables control charts, in order to verify the ability of each estimator to identify out-of-control conditions.