1 / 25

# XmR Chart - PowerPoint PPT Presentation

XmR Chart. Farrokh Alemi, Ph.D. Purpose of Control Chart. Real or random. Tell a story of changes in outcomes of the process. Moving Range. Moving Range. Moving Range. Moving Range. Most common approach. Which Chart is Right?. Assumptions of XmR chart. Assumptions.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

## PowerPoint Slideshow about ' XmR Chart' - channing-melendez

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

### XmR Chart

Farrokh Alemi, Ph.D.

• Real or random.

• Tell a story of changes in outcomes of the process.

Farrokh Alemi, Ph.D.

Farrokh Alemi, Ph.D.

Farrokh Alemi, Ph.D.

Farrokh Alemi, Ph.D.

Most common

approach

Farrokh Alemi, Ph.D.

Assumptions of XmR chart

• There is one observation per time period

• Observations are measured in an “interval” scale

• Observations are independent of each other

Farrokh Alemi, Ph.D.

Pre-intervention

Farrokh Alemi, Ph.D.

Selection of Time Period

Farrokh Alemi, Ph.D.

Observation at time “t”

Absolute value of difference of two consecutive observations

Calculate Average Moving Range for 2 Consecutive Values

Farrokh Alemi, Ph.D.

Upper Control Limit = Average of observations + E * Average of moving range

Lower Control Limit = Average of observations - E * Average of moving range

Farrokh Alemi, Ph.D.

E Depends on Number of Time Periods in the Range

Farrokh Alemi, Ph.D.

• Diabetes patient measured weight for 16 weeks

• First 7 weeks were pre-intervention

• Has the patient’s weight changed?

Farrokh Alemi, Ph.D.

• One observation per time period

• Interval scale

• Independent observations

Farrokh Alemi, Ph.D.

2. Select Pre- Or Post-Intervention Period

Farrokh Alemi, Ph.D.

Farrokh Alemi, Ph.D.

Farrokh Alemi, Ph.D.

Farrokh Alemi, Ph.D.

Farrokh Alemi, Ph.D.

• UCL = 197.43 + 2.66 * 2.67 = 204.52

• LCL = 197.43  - 2.66 * 2.67 = 190.33

Farrokh Alemi, Ph.D.

• Plot the x and y axis, plot the observations

• Plot the limits as line with no marker

• Plot solid line for pre-intervention period

Farrokh Alemi, Ph.D.

• Points outside the limits show real changes in outcomes of the process

Farrokh Alemi, Ph.D.

• Distribute the chart by electronic media, as part of company newsletter, or as an element of a story board display

• Keep following in mind:

• Show that you have verified assumptions

• Check that your chart is accurately labeled

• Include your interpretation of the finding

Farrokh Alemi, Ph.D.

### Take Home Lesson

How and When to Construct an XmR chart