A Control Chart For $R$ Is Shown Below

question 18

Essay

A control chart for $R$ is shown below. 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.

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Definitions:

Groundwater

Soil water and water in aquifers.

Aquifers

Underground layers of water-bearing permeable rock, rock fractures, or unconsolidated materials from which groundwater can be extracted using a water well.

Lakes

Large bodies of water surrounded by land, freshwater or sometimes saline, that are inland and not part of the ocean.

Rivers

Large natural streams of water flowing in channels to the sea, a lake, or another river.