Hi
Sorry for the lack of clarity in the title heading - I couldn't think of
a clearer way of putting it!
I have been asked to read over a script, and there is something niggling
at the back of my mind about it.
The study involves taking measurements from two groups of subjects. In
group A the subjects were measured for 1 day, in group B the subjects
were measured for three days and for each individual the results were
'averaged' i.e. a mean daily value was calculated for each individual.
A comparison was then made between the values obtained from the two
groups (using t tests/mann-whitney etc).
I was wondering whether these comparisons were 'like with like'. I feel
that the averaging process would tend to result in decreased variation
in the data from group B; however, I am not sure that this is the case,
and don't know what the implications would be for interpreting
statistical tests.
Sorry for the possibly 'basic' question; however any help/advice
references would be most appreciated.
Regards
Graham
--
Dr G.S.Clarke Dr G S Clarke
Lecturer in Physiology Darlithydd mewn Ffisioleg
& Biometry a Biometreg
UWB Teaching Fellow Cymrawd Addysgu PCB
School Of Healthcare Sciences Ysgol Gwyddorau Gofal Iechyd
College of Health Coleg Gwyddorau Iechyd
& Behavioural Sciences ac Ymddygiad
University of Wales, Bangor Prifysgol Cymru, Bangor
Fron Heulog Fron Heulog
Ffriddoedd Road Ffordd Ffriddoedd
Bangor Bangor
Gwynedd LL57 2EF Gwynedd LL57 2EF
Tel: 01248 383157 Ffôn: 01248 383157
e-mail: [log in to unmask] e-bost: [log in to unmask]
--
Gall y neges e-bost hon, ac unrhyw atodiadau a anfonwyd gyda hi,
gynnwys deunydd cyfrinachol ac wedi eu bwriadu i'w defnyddio'n unig
gan y sawl y cawsant eu cyfeirio ato (atynt). Os ydych wedi derbyn y
neges e-bost hon trwy gamgymeriad, rhowch wybod i'r anfonwr ar
unwaith a dilëwch y neges. Os na fwriadwyd anfon y neges atoch chi,
rhaid i chi beidio â defnyddio, cadw neu ddatgelu unrhyw wybodaeth a
gynhwysir ynddi. Mae unrhyw farn neu safbwynt yn eiddo i'r sawl a'i
hanfonodd yn unig ac nid yw o anghenraid yn cynrychioli barn
Prifysgol Cymru, Bangor. Nid yw Prifysgol Cymru, Bangor yn gwarantu
bod y neges e-bost hon neu unrhyw atodiadau yn rhydd rhag firysau neu
100% yn ddiogel. Oni bai fod hyn wedi ei ddatgan yn uniongyrchol yn
nhestun yr e-bost, nid bwriad y neges e-bost hon yw ffurfio contract
rhwymol - mae rhestr o lofnodwyr awdurdodedig ar gael o Swyddfa
Cyllid Prifysgol Cymru, Bangor. www.bangor.ac.uk
This email and any attachments may contain confidential material and
is solely for the use of the intended recipient(s). If you have
received this email in error, please notify the sender immediately
and delete this email. If you are not the intended recipient(s), you
must not use, retain or disclose any information contained in this
email. Any views or opinions are solely those of the sender and do
not necessarily represent those of the University of Wales, Bangor.
The University of Wales, Bangor does not guarantee that this email or
any attachments are free from viruses or 100% secure. Unless
expressly stated in the body of the text of the email, this email is
not intended to form a binding contract - a list of authorised
signatories is available from the University of Wales, Bangor Finance
Office. www.bangor.ac.uk
|