Correlation,Social Psychology N

2002-02-22 Thread christian

Hi,
i calculate some calculations for a specific target variable.
People should rate for 3 things some independends and one dependend
variable. People should not difference in importances as possible 
between the 1.,2.and the 3.Chose.
Now i filter all people which rate the same thing (i.e. a 
Product/Company) and calculate the different correlations dependend
from the thing is rated as 1./2./3. or all togehter!

Not a surprise for me are the different values in correlation, but
make the use of correlations for this doubtful.
What is more a cause for this results'S ?
(1) The small N's
(2) The social-psychological phenomen that people
want prefer something and not really indifferent when they ask for 3 
rating's relative to a product/company.

Result:
So people who rate a product/company as 1. and others as 2. or 3.
( what is not a ranked order but it works neverthless in consciousness ) 
must be different analyze, because their exist different attitudes ?



r 
N 
r 
N 
r 
N 
r 
N 

1.Chose 
2.Chose 3.Chose Cummulate 1. to 3.Choose
0.53 
28 
0.66 
23 
0.19 
20 
0.43 
71
0.13 
28 
0.28 
22 
0.41 
22 
0.25 
72
0.37 
23 
0.34 
24 
0.17 
22 
0.28 
69
0.50 
20 
0.02 
17 
0.48 
17 
0.35 
54
0.55 
27 
0.54 
22 
0.44 
20 
0.52 
69
0.14 
21 
0.20 
19 
0.15 
16 
0.21 
56
0.13 
27 
0.10 
22 
0.26 
20 
0.17 
69
0.75 
24 
0.38 
21 
0.28 
18 
0.51 
63
0.51 
23 
0.36 
18 
0.57 
18 
0.50 
59
0.83 
26 
0.46 
22 
0.29 
20 
0.57 
68


Thanks for any suggestion, alternatives
and regards, Christian




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Graphics CORRESPONDENCE ANALYSIS

2001-10-22 Thread christian

Hello,

...have anybody experience or a good idea
how i can display the result from the correspondence analysis
in a better way like spss (i.e. excel ), because the visual performance 
in my humble opinion is not the best !?

thanks for advance 
regards, christian



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K-Means QuickClusteranalysis (OptimalSolution)

2001-10-01 Thread Christian

Hello,
i look for a good way to find the 
optimal number of cluster for a special problem !

Is it right to sum the distanceValues^2 and look for the point
where these sumOfEuclideanDistance have the most lost from one to the
next ClusterSolution ?

P.S. 
I hope my english is not to bad ;-(

thanks for advance 
regards christian


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comparing factor patterns ?

2001-08-28 Thread Dr. Hans-Christian Waldmann



Hi everybody!

Sure thing that some will find this request annoying and pointless again,
but there's still a lot of confusion about it. Yes, we do want to compare
factor patterns. Actually we need to evaluate whether factorial structures
of 2 tests are similar enough, roughly, to assume they're parallel. For my
own part I think one should use LISREL (or the like), constrain the loadings
of one model to the other one, and evaluate (mis)fit. It shouldn't be too
hard to set this up in SAS. Unfortunately, our client insists on keeping to
SPSS (no LISREL module) and now asks for a formal comparison of two explo-
ratory PCAs. He doesn't want to hear that it cannot be done. Still, I feel
that I should collect some opions on the issue before giving up. Anybody out
there to provide some hints ?

Thank you in advance for your consideration!

Hans


-
PD Dr. Hans C Waldmann  
Methodology  Applied Statistics in Psychology  the Health Sciences

ZFRF / University of Bremen / Grazer Str 6 / 28359 Bremen / Germany 
[EMAIL PROTECTED] 
http://samson.fire.uni-bremen.de/waldmann

friend of: AIX PERL POSTGRES ADABAS SAS TEX 
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the gallup international millenium survey

2001-05-19 Thread Christian Bechmann Pedersen


Hi,

Oops wrong email before, sorry

Does anyone have any experience on analyzing the millenium survey 2000, by
gallu international, when all the data is aggregatet to mean values for each
country?
In that respect I have a problem with discussing alternative interpretations
of the four democracy segments presentet by GI  , when
the only availlible data is the above.
Does it make any sense to construct a index bassed on mean values.

Anyone know any links concerning the gallup international millenium survey
2000, other than the gallup.com

any help is much appriciated

thanks,

C. Bechmann







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Re: reasonable probability

2000-12-06 Thread Christian Bau

In article 90k3vl$[EMAIL PROTECTED], [EMAIL PROTECTED]
(Herman Rubin) wrote:

 AFAIK there is general agreement that unbiased humans are better at
 identifying  the difference between unpunched holes and imperfectly
 punched holes than current counting machines -- which after all were
 only designed to distinguish between unpunched and perfectly punched
 holes.
 
 UNBIASED humans, yes.  There is considerable evidence of bias.
 
 Some of this bias is inadvertent, the type of observer bias 
 found in many experimental situations in other fields.  This 
 is especially the case if it is not merely a piece of hanging
 chad, but a dimple.  It also occurs if there is a question
 of multiple voting for an office.

Both the United Kingdom and Germany use the old fashioned
piece-of-paper-take-a-pencil-mark-your-candidate method, and the papers
are always handcounted. 

I don't think there is ever any question about "voter intention" unless a
voter deliberately chooses to make his ballot paper undecidable. Just
because a system is oldfashioned doesn't mean it can't be better anyway.


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Summary: 120 subjects on 120 occasions

2000-10-17 Thread Dr. Hans-Christian Waldmann



Dear List(s),

Last week I have posted a request for help pertaining to the issue
of how to analyse repeated measurement data with some rather unusual
dimensions (N=120 subjects giving a time series with T=120 occassions
each). To my pleasure, there have been as much as 12 replies which are
given below. Beforehand, the original posting is given.

For those of you who don't want to read through all of these, here is
a short summary.


Roughly, responses/recommendations can be classified into 5 categories:


 a) Make use of all information available and put them into a form
suitable for state-space models or vector-ARIMA-analyses.

Frankly: this seems to go beyond my capabilities, and I am 
inclined to take the penalty of reducing the data as pro-
posed by other responders.


 b) Perform time series analyses for each subject and boil the
data down to certain parameters. Read these into a secondary
data set and merge it somehow with the original one in order to 
preserve design variables like treat/control, sex and age or the 
like. Finally, use these data for "standard" analyses to test for 
hypotheses of homogeneity of subjects within groups or differences
across groups (implying some MANOVA-style model).

Going to extremes, one could obtain a single parameter like a slope
for each subject and perform univariate analyses with regard to
higher stratum levels.

Another response in this direction suggested fitting a spline
model for each subject and use spline components for subsequent
ANOVA-style models. I understand that this could be done using
proc transreg in SAS, but I am not sure whether this procedure does
in fact account for the time dependency in the individual data giving
the spline.


 c) Reduce the repeated measurement frequency in the first place and
then perform (M)ANOVA-style analyses with a time factor of (then)
suitable level count. Test for time effects using standard contrast
like polynomial decomposition or helmert coefficients (when interest
lies with the point in time when responses cease to change any 
further).


 d) A particuarly interesting response suggested identifying "change 
profiles" within time series and submitting these to further analyses 
like permutation test. Still, I am unclear about how to aggregate data
in order to make best use of all subjects' data.


 e) General remarks and caveats like paying regard to sample size issues,
looking for cyclicity in individual data that generalze to the stratum,
adjusting for cross-correlations in case of multi-variable outcome
measures, and the complexity of assumptions required when analysing
complex factorial designs involving a repeated measures factor.



Again, thanks to all who took their time to help. I am committed to parti-
cipate in this way of mutual assistance.

Hans C Waldmann



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Dr. Hans C Waldmann  
Methodology  Applied Statistics in Psychology  the Health Sciences

ZFRF / University of Bremen / Grazer Str 6 / 28359 Bremen / Germany 
[EMAIL PROTECTED] / http://samson.fire.uni-bremen.de

friend of: AIX PERL ADABAS SAS TEX 
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Following:
 0) Original posting (request)
  1-12) replies




0)



- Original Message -----
From: "Dr. Hans-Christian Waldmann" [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Thursday, October 12, 2000 2:18 PM
Subject: a model for time series (T=120) for N=120 persons ?




 Hello everybody,

 in one of the clinical projects we consult on data analysis, I am
 facing a problem I have not yet come across and that leaves me with no
 idea on how to proceed. The problem pertains to the dimension of
 the outcome data set. In a repeated measures design, let N be the
 number of people treated and T be the number of measurement occassions.

 I understand that N=1 (or _some_) more and T=120 would make up a time
 series, and that I am supposed to fit ARIMA-MOdels or Transfer functions.
 I could detect effects by structural breaks around the point of time of
 intervention, that is: performing intervention analyses as proposed in
 McDowell, McCleary, Meidinger and Hay, 1980, Interrupted time series
 analysis, or other books on how to analyse data from single subject
 designs.
 Allright.

 I understand that N=120 (or any number more) and repeated measures like
 2=T="the-smaller-the-better" would make up a dataset suitable for
 an ANOVA approach or mixed models using special covariance structures
 like SAS's proc mixed. I know how to do that.
 Allright.

 I understand that for each of this variants there are some alternatives
 in statistical modeling (like non-parametric analyses etc.).

 Now,

120 subjects on 120 occassion: a model ?

2000-10-12 Thread Dr. Hans-Christian Waldmann

Hello everybody,

in one of the clinical projects we consult on data analysis, I am 
facing a problem I have not yet come across and that leaves me with no 
idea on how to proceed. The problem pertains to the dimension of 
the outcome data set. In a repeated measures design, let N be the 
number of people treated and T be the number of measurement occassions.

I understand that N=1 (or _some_) more and T=120 would make up a time
series, and that I am supposed to fit ARIMA-MOdels or Transfer functions.
I could detect effects by structural breaks around the point of time of
intervention, that is: performing intervention analyses as proposed in
McDowell, McCleary, Meidinger and Hay, 1980, Interrupted time series
analysis, or other books on how to analyse data from single subject 
designs. 
Allright.

I understand that N=120 (or any number more) and repeated measures like
2=T="the-smaller-the-better" would make up a dataset suitable for 
an ANOVA approach or mixed models using special covariance structures
like SAS's proc mixed. I know how to do that.
Allright.

I understand that for each of this variants there are some alternatives
in statistical modeling (like non-parametric analyses etc.).

Now, what am I supposed to do with data from a design giving a T=120 
time series for _each_ of 120 subjects ? There has been a controlled 
study where patients in three independent groups were asked to keep 
a diary on some outcome variables for ca. 4 months. There are some
design variables like treat/control or sex and age that are expected
to contribute systematically to variation between outcome measures.
But this outcome measure apparently is a time series. I don't think 
I should perform an ANOVA-style analysis with a 120-level time factor.
Pooling data and performing ARIMA/transfer-functions on a single time 
series of subjects' means for each point in time doesn't make sense
either, assuming that subjects differ in both measurement level and 
covariance structure of their individual time series. I admit that
I have no idea how to evaluate, say, an effect of treatment on this
kind of outcome measure. 

Does anybody else have an idea ? I promise to post a summary of res-
ponses to the list.  


Thanks in advance

Hans-Christian Waldmann


-
Dr. Hans C Waldmann  
Methodology  Applied Statistics in Psychology  the Health Sciences

ZFRF / University of Bremen / Grazer Str 6 / 28359 Bremen / Germany 
[EMAIL PROTECTED] / http://samson.fire.uni-bremen.de

friend of: AIX PERL ADABAS SAS TEX 
-


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Adjusting a Correlation Matrix

2000-07-06 Thread Christian A. Walter

Does anyone know if there is a structured way to adjust a negative
definite matrix such that it becomes semi-definite, while "minimizing"
the induced changes to the matrix?

Cheers,
Christian


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programming stata 6

2000-03-14 Thread Christian Galonska

I'm a beginner in using stata 6.0. I wrote ado-files for calculating the
gini coefficient and the index of dissimilarity. However the 'by', 'if' and
'in' syntax don`t work correctly. Who can help me?




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