“…But, in practice, an exact measurement is a rare phenomenon in any of the situations where human involvement is evident. The effect of measurement errors has been intensively investigated for a number of mean-or variance-type charts, and the conclusion is that the performance of these charts is always negatively affected in presence of such errors, see, for instance, Linna and Woodall, 25,26 Maravelakis et al, 27 Shore, 28 Chang and Nikzad, 29 Chakraborty and Khurshid, 30 Amiri and Nikzad, 31 Khati Dizabadi et al, 32 Ghashghaei et al, 33 Tran et al, 34 Daryabari et al, 35 Sabahno and Amiri, 36 Castagliola et al, 37 and Salmasnia et al 38 The measurement errors model the most commonly used in the literature is the linear covariate model, proposed by Linna and Woodall,25 ie, Y = A + BX + , where A and B are known constants and is a random error due to the measurement imprecision. In this paper, they investigated the properties of the ShewhartX and the S 2 charts with measurement errors, and they suggested taking multiple measurements to compensate for the effect of measurement errors, Maravelakis et al 27,39 evaluated the performance of the EWMAX and the CUSUMX charts, respectively, in the presence of measurement errors using the same linear covariate model.…”