Abstract: In this paper we investigate the effect of non-normality and auto-correlation on the OC function of mean chart with known coefficient of variation. We synthesize the second order auto-correlation process by its three different roots. In particular, the shift in the auto-correlation structure from independent data to a random walk, this is a special case of the structural shift occurring in the process. For various values of roots the values of OC functions are tabulated with known coefficient of variation.