Use EWMA Chart to detect small shifts in the process mean, without influence by low and high values. The EWMA chart monitors exponentially weighted moving averages, which remove the influence of low and high values. The observations can be individual measurements or subgroup means. An advantage of EWMA charts is that they are not greatly influenced by low or high values.
To create an EWMA chart, choose .
If you do not want to detect small shifts in a process, use a variables chart for subgroups, such as Xbar-R Chart, or an variables chart for individuals, such as I-MR Chart.