Explanation: EWMA charts and the cusum charts both, find applications in the short production run cases. This is due to the fact that the EWMA charts and the Cusum charts both have shorter ARL than the Shewhart charts.

Explanation: The Cusum charts are effective for subgroups size of one. The self starting version of the Cusum charts is particularly suitable for the short run environment due to the same fact.

Explanation: The self starting approach of cusum charts uses regular process measurements for both establishing the cusum, and calibrating of cusum. These measurements are also used for process monitoring.

Explanation: The self starting approach uses regular process measurements for establishing and calibrating the cusum, and for process monitoring. Thus, this eliminates the phase I parameter estimation stage.

Explanation: The number of subgroups used in calculating the trial control limits for Shewhart control charts, impacts the false alarm rate of the chart. This rate is inflated when small number if subgroups is used.

Explanation: The false alarm rate of the Shewhart control charts also depends over the number of subgroups used to construct the trial control limits. This was first studied by Hillier (1969).

Explanation: Quesenberry recommended the Q charts to be used in the place of the Shewhart control charts, in the case of small subgroup number used to calculate the control limits. This was because small number of subgroups used with Shewhart control charts, increased their FAR.

Explanation: Del Castillo and Montgomery found the ARL performance of the Q-charts very inadequate. So, they recommended the Kalman filter that has a better ARL performance than Q-chart.

Explanation: The control charts are generally plotted for the main reasons like control of the process or statistical monitoring, reduction of variability, and continuous process improvement.

Explanation: At the stage, when the process has achieved a high level of capability, there is some relaxation provided to the level of the surveillance provided. This is generally done with modified control limits in the case of x charts.

Explanation: The relaxation in the case of x charts in the case of high process capability is provided with the use of the modified limits. These are also called reject limits.

Explanation: When the process capability becomes very high, the relaxation of the level of surveillance is provided by using two methods; first is the reject limits, and the second is the acceptance control chart.

Explanation: The modified control limits are used when the process capability is very high. The PCR Cpk≫1, very less process spread, and low natural variability indicate the high process capability. So, modified control charts are used in these conditions.

Explanation: As six-sigma approach to variability reduction focuses on improving process until the minimum value of Cpk=2. So this means high process capability, which encourages modified control charts usage.

Explanation: The modified control charts have the use of the modified control limits, which are used when the process capability is high or Cpk≫1. As Cpk=0.9899, the usage of modified control charts is not necessary.