Turn on suggestions

Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type.

Showing results for

- JMP User Community
- :
- Discussions
- :
- Discussions
- :
- Multivariate Control Chart: Upper Control Limit

Topic Options

- Start Article
- Subscribe to RSS Feed
- Mark Topic as New
- Mark Topic as Read
- Float this Topic for Current User
- Bookmark
- Subscribe
- Printer Friendly Page

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Get Direct Link
- Email to a Friend
- Report Inappropriate Content

Multivariate Control Chart: Upper Control Limit

Jun 28, 2010 8:04 PM
(1312 views)

Hi there,

In the chapter of "Multivariate Control Charts" > "Ungrouped Data" > "Phase 1 - Obtaining Targets" I couldn't get the UCL value of 11.03 by following the formula shown in "Statistical Details".

Is there anyone out there kind enough to clarify?

Cheers,

CGC.

In the chapter of "Multivariate Control Charts" > "Ungrouped Data" > "Phase 1 - Obtaining Targets" I couldn't get the UCL value of 11.03 by following the formula shown in "Statistical Details".

Is there anyone out there kind enough to clarify?

Cheers,

CGC.

4 REPLIES 4

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Get Direct Link
- Email to a Friend
- Report Inappropriate Content

Re: Multivariate Control Chart: Upper Control Limit

Go to Help> Sample Data

Click Alphabetical List of Files

Navigate to Steam Turbines Historical and click link to file

Go to Graph>Control Chart> Multivariate Control Chart

Add Fuel, Steam Flow, Steam Temp, MW, Cool Temp, & Pressure to the Y Columns

Click OK

I get a UCL of 11.03

Click Alphabetical List of Files

Navigate to Steam Turbines Historical and click link to file

Go to Graph>Control Chart> Multivariate Control Chart

Add Fuel, Steam Flow, Steam Temp, MW, Cool Temp, & Pressure to the Y Columns

Click OK

I get a UCL of 11.03

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Get Direct Link
- Email to a Friend
- Report Inappropriate Content

Re: Multivariate Control Chart: Upper Control Limit

Yeah that's the value we could get by following the charting procedures but you wouldn't be able to get the same result by calculating it using the formulae given.

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Get Direct Link
- Email to a Friend
- Report Inappropriate Content

Re: Multivariate Control Chart: Upper Control Limit

With n=28 and p=6 and alpha=0.05 the one sided level of risk, the following formula agrees with the JMP multivariate control chart output (i.e. 11.03):

(((n-1)^2) / n) * beta quantile(1-alpha, p/2, (n-p-1)/2)

There seem to be a couple of issues with the documentation.

1. n is incorrectly defined for ungrouped data. It should be the number of data points, not the group sample size

2. The definition of alpha in the docs is not made clear but appears to be what I have written as 1-alpha with alpha the one sided level of risk

Michael

(((n-1)^2) / n) * beta quantile(1-alpha, p/2, (n-p-1)/2)

There seem to be a couple of issues with the documentation.

1. n is incorrectly defined for ungrouped data. It should be the number of data points, not the group sample size

2. The definition of alpha in the docs is not made clear but appears to be what I have written as 1-alpha with alpha the one sided level of risk

Michael

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Get Direct Link
- Email to a Friend
- Report Inappropriate Content

Re: Multivariate Control Chart: Upper Control Limit

You're right Michael, I was first confused with the "n" notation, the type of "function of beta distribution" and the "first argument" of the function. The technical support team admitted the mistakes and confirmed "n" to be the total sample size, the "function" beta quantile function and the "first argument" (1-alpha).

There are errors in the documentation for Phase 2 as well, fyi.

There are errors in the documentation for Phase 2 as well, fyi.