Hello All,
Sorry for the longish e-mail; but I am seeking your advice/opinion on
two questions:
1) I have a data set to analyse regarding a range of professionals'
response to a questionnaire. I have done PCA on all the results and
then follow up investigation to see which professional groups differ
from other professional groups with respect to the derived components.
However in looking to publish the results it is clear that some journals
would be more interested in a subset of those professional groups. So
how to proceed? I could use the PCs as derived from all the
questionnaires to generate 'scores' for all individuals which I then
analyse for the sub set of professions; or I could generate PCs derived
only from individuals belonging to the sub set of professions and
analyse those (these PCs are similar but not identical).
In doing further (effectively post-hoc) analysis on all the professions
my subset professions are often placed in different 'homogeneous groups'
however when I simply work with the sub set of professions then the
analysis more frequently says that these subset professions belong to
one 'homogeneous group' (presumably because of the reduction in overall
sample size is reducing power). (One of my sub set professions has only
8 members compared to ~50, ~100 in the other two sub set professions;
the overall - all professions - sample size is about 1200.)
So really, my question how to proceed with analysing the sub-set of
professions. What is the more effective/rigorous analysis in terms of
statistics and also in terms of what editors of journals may accept.
Any advice/opinon/references would be welcomed
Question. - pretty much separate from Q1.
In terms of ranking type data, simpler type analyses can be carried out
'non parametrically' using techniques found in texts like siegal and
castalan. However I was wondering how to approach analyses that - had
the data being normal etc. you would use a multiple regression/factorial
ANOVA . Any advice on this would be welcome as would any recommendations
for any text I could read that would give me info on this (I do have a
maths degree, but it is a bit 'rusty' so application rather than theory
would be preferred).
Sorry to take up so much of your time, but any help with either (or
both!) these questions would be very gratefully received.
Best Regards
Graham
--
Dr G.S.Clarke
Lecturer in Physiology & Biometry
Faculty of Health Studies
University of Wales, Bangor
Fron Heulog
Ffriddoedd Road
Bangor
Gwynedd LL57 2EF
Tel: 01248 383157
e-mail: [log in to unmask]
--
Dr G.S.Clarke
Lecturer in Physiology & Biometry
Faculty of Health Studies
University of Wales, Bangor
Fron Heulog
Ffriddoedd Road
Bangor
Gwynedd LL57 2EF
Tel: 01248 383157
e-mail: [log in to unmask]
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