An extension of the graded response model of Samejima (1969) for the measurement of variability and change is presented. In this model it is assumed that an occasion-specific latent variable is ...

_MEAN_ process mean (value of central line on box chart) _R_ value of central line on R chart _S_ value of central line on s chart A subgroup standard deviation variable is included if you specify the ...

Steven Nickolas is a writer and has 10+ years of experience working as a consultant to retail and institutional investors. Portfolio variance is a measure of the dispersion of returns of a portfolio.

You can read raw data (process measurements) from a DATA= data set specified in the PROC SHEWHART statement. Each process specified in the SCHART statement must be a SAS variable in the DATA= data set ...