The Variables

i think the two variables are MEAN and VARIANCE.

MEAN because it means that there is no changes or everything is going to plan. no improvements and downstreams in the system. in terms items or products, everything is on the average.

VARIANCE because it means that there is changes. there is improvement or downstreams in the system. in terms of items and products, there are defective and non-defective items.

when you ask your managers in your company, you should ask if there are changes or if everything is going as planned. if there are changes, is it for the better or for the worst.