1) A tendency for points to cluster the center line of control chart is what answer
2) Indicated when the plotted points tend to fall near or slightly outside the control limits with relatively few points near the center line is what answer
3) May result from the introduction of a new worker changes in methods , raw material or machine a change in the inspection method or standards or change in either the skill attentiveness or moviation of the operators is what answer
4) Occasionally appear on the control results from systematic environmental changes such as temperature, operator fatigue, regular rotation of operators and /or machines,or fluctuations or some other variable.