From: Tyler Rinker <tyler_rinker_at_hotmail.com>

Date: Sun, 20 Mar 2011 05:59:06 -0400

R-help_at_r-project.org mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Sun 20 Mar 2011 - 10:03:56 GMT

Date: Sun, 20 Mar 2011 05:59:06 -0400

My aplogies:

The Table of effects did not come through as I had intended them to. HEre they are reformatted: Again I would like to see someone actually run mahalanobis() for this data set to arrive at ?1 and ?2. I do not know what exactly (after reading the manual) goes in for x,center,or cov. Seeing an actual [R] printout of it being done (from start to finish) would go a long way towards my learning.

Effect Sizes Contrasts| Dependent Variables Friends Parents Strangers All Young-Middle -1.8768797* -3.2842941* -1.1094004* ?1 Middle-Old 1.34900725* 1.54919532* -2.0107882* ?2

Gender Age, Friend.Agression, Parent.Agression, Stranger.Agression
1 f y 8 7 8

2 f y 5 6 8

3 f y 6 3 7

4 f y 5 5 7

5 f m 15 13 10

6 f m 13 11 9

7 f m 12 12 9

8 f m 18 10 7

9 f o 11 11 10

10 f o 10 4 12

11 f o 12 9 12

12 f o 9 8 14

13 m y 13 7 7

14 m y 9 5 10

15 m y 11 4 4

16 m y 15 3 4

17 m m 14 12 8

18 m m 10 15 11

19 m m 12 11 8

20 m m 10 9 9

21 m o 10 8 11

22 m o 13 11 13

23 m o 9 8 12

24 m o 7 9 16

*> From: tyler_rinker_at_hotmail.com
**> To: r-help_at_r-project.org
**> Date: Sun, 20 Mar 2011 01:53:47 -0400
**> Subject: [R] Using the Mahalanobis Function
**>
**>
**>
**>
**>
*

> Hello all,

*>
**> I am a 2 month newbie to R and am stumped. I have a data set that I've run multivariate stats on using the manova function (I included the data set). Now it comes time for a table of effect sizes with significance. The univariate tests are easy. Where I run into trouble filling in the table of effect sizes is the Mahalanobis D as an effect size. I've included the table so you can see what group's I'm comparing. I know there's a great function for filling in ?1 and ?2 : mahalanobis(x, center, cov, inverted=FALSE, ...)
**>
**> The problem is I lack the knowledge around cluster analysis of what goes into the function for [x, center, & cov.] I have only a basic understanding of this topic (a picture of a measured distance between two clusters on a graph). Could someone please use my data set or a similar one (a multivariate with at least 3 outcome variables) and actually run this function (mahalanobis). Then please send me your output from [R] starting from the data set all the way to the statistic. PS I know the Mahalanobis D should be ?1=3.93 & ?2=3.04.
**>
**> The Y,M,O in the data set stands for young, middle, old.
**>
**> I am running the latest version of R on a windows 7 machine.
**>
**>
**>
**>
**>
**>
**> Effect Sizes
**>
**>
**>
**> Contrasts
**>
**> Dependent Variables
**>
**>
**>
**>
**>
**>
**> Friends
**>
**> Parents
**>
**> Strangers
**>
**> All
**>
**>
**> Young-Middle
**>
**> -1.8768797*
**>
**> -3.2842941*
**>
**> -1.1094004*
**>
**> ?1
**>
**>
**> Middle-Old
**>
**> 1.34900725*
**>
**> 1.54919532*
**>
**> -2.0107882*
**>
**> ?2
**>
**> Gender Age Friend.Agression Parent.Agression Stranger.Agression
**> 1 f y 8 7 8
**> 2 f y 5 6 8
**> 3 f y 6 3 7
**> 4 f y 5 5 7
**> 5 f m 15 13 10
**> 6 f m 13 11 9
**> 7 f m 12 12 9
**> 8 f m 18 10 7
**> 9 f o 11 11 10
**> 10 f o 10 4 12
**> 11 f o 12 9 12
**> 12 f o 9 8 14
**> 13 m y 13 7 7
**> 14 m y 9 5 10
**> 15 m y 11 4 4
**> 16 m y 15 3 4
**> 17 m m 14 12 8
**> 18 m m 10 15 11
**> 19 m m 12 11 8
**> 20 m m 10 9 9
**> 21 m o 10 8 11
**> 22 m o 13 11 13
**> 23 m o 9 8 12
**> 24 m o 7 9 16
**>
**> [[alternative HTML version deleted]]
**>
**> ______________________________________________
**> R-help_at_r-project.org mailing list
**> https://stat.ethz.ch/mailman/listinfo/r-help
**> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
**> and provide commented, minimal, self-contained, reproducible code.
*

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https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Sun 20 Mar 2011 - 10:03:56 GMT

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