Quality Control
Charts :X-bar Chart
Suppose that you are trying to monitor the amount of moisture in a fabric. (This data is listed in the STA 3032 notes.) Five measurements were taken at a time.
Enter Data where
each row is a sample:
To do this entire sample 1, in row 1. Enter sample
2 in row 2.
X-bar
–S Chart
- If
you want to do a X-bar Chart with s as an approximation of sigma, go to
Stat, Control Charts, Variables charts for subgroups, X-bar-s. The following image will
appear.
- Select “Observations for a subgroup are in one row of
columns”.
- Enter the columns, which contain your data.
- Click on X-bar-S options and click on Estimate. The
figure below will appear.
- Select Sbar.
- Click o.k. twice. The following graph will appear. The
top chart is an X-bar chart that uses s to estimate sigma. The second
graph is an s chart.
X-bar –R
Chart
- To
do a quality control chart that uses the range instead of s go
to Stat, Control Charts, Variables charts for subgroups, X-bar-s. The following image will
appear.
- Select “Observations for a subgroup are in one row of
columns”.
- Enter the columns, which contain your data.
- Click on X-bar-R options and click on Estimate. The
figure below will appear.
- Select Rbar.
- Click o.k. twice. The following graph will appear. The
top chart is an X-bar chart that uses r to estimate sigma. The second chart is an r chart.
