# X-bar and R-Chart

The dataset contained in the problem #4 Excel file gives data on moisture content for specimens of a certain type of fabric.

a. Create an X-bar R chart, using the first 10 subgroups as the base period. Comment on what is shown.

b. What did you assume to construct these control limits (be specific)? Check the assumptions. Given the information in the base period, how comfortable are you with these assumptions?

c. Repeat part a using the 3 additional runs rules; comment on your findings being sure to state what each rule requires.

See the attached files below for datasheet

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#### Solution Preview

The X-bar and R( range) is a pair of control charts used with processes that have subsize of two or more.

The X bar shows how the mean or average changes over time

The R chart shows how the range of the subgroups changes over time.

The X bar shows how the mean or average of each subgroup ...

#### Solution Summary

The X-bar and R( range) is a pair of control charts used with processes that have subsize of two or more.

The X bar shows how the mean or average changes over time. The R chart shows how the range of the subgroups changes over time. 228 words and an Excel attachment.