Let each subgroup consist of the 6 values within a year. Construct an R chart and determine whether the process variation is within statistical control. If it is not, identify which of the three out-of-control criteria lead to rejection of statistically stable variation.

Refer to the amounts of energy consumed in the author€™s home. Each value represents energy consumed (kWh) in a two-month period. Let each subgroup consist of the six amounts within the same year.

9-4-8 8-6-7 8-9-8-8-9-1-0 7-2 9-2-3-6-2-5 0 8-2-1-3 8 6-4 8 2|1|2 7 5-2-7-6-1-3 1 2 3 4 5 6 7 8