On the other hand, if we considered our dataset follows ARMA(1,1), then Shewhart should be the most efficient control chart design. If we
selected our adequate model to be AR(1), then the representative autocorrelation ∅ should equal 0.574, and if ARMA(1,1), the
autocorrelation ∅ and θ should equal to 0.45 and 0.198, respectively