I find the SPSS list really helpful. Though my hotmail account gets
bombarded with about 50 e-mails a day. Saying that, it takes minutes to
scroll the e-mail title and choose to read relevant ones. I suppose it
might be a good idea to set up a separate hotmail account for such
e-mails, though I think the 4 I have will suffice for now!
Kathryn
>>> Jeremy Miles <[log in to unmask]> 22/03/2007 21:29:08 >>>
It's worth getting on the spssx-l list too, and seeing what people
say. (Most of it's dull, but the odd bit is useful). There's a
psych-methods list too, on jiscmail, and there are lists for other
stats packages (I'm on R and Stata) , and other techniques, if you use
them. (E.g. there's a multilevel modelling list, and a structural
equation modelling list).
Jeremy
On 22/03/07, leah quinlivan <[log in to unmask]> wrote:
> Hi,
>
> I just like to say, the list is brilliant, and I really appreciate,
poking
> my nose into other discussions. Ive learned more about stats than in
any
> class, and tis making us all more rigorous, critical researchers. Im
really
> interested in stats also, but I'm only a toddler in stats land!
>
> A definite thanks,
>
> Leah
>
>
>
> On 22/03/07, Kathryn Jane Gardner <[log in to unmask]> wrote:
> > re: meta analysis (which i've never used), I am presenting the
means and
> > effect sizes (I thought the latter was used in meta analyses), just
not
> > running the t test.
> >
> > I'll seeks out Abelson's book then! Might treat myself from
Amazon.
> >
> > Maybe that's why Patrick McGhee rings a bell (if he's a the top).
Oh
> > dear, should I know more about this?? :-) I know who the vice
chancellor
> > is so i'm happy with that for now :-)
> >
> > Thanks for all your help Jeremy. I know others on the list will
> > appreciate these discussions as much as I do.
> > Kathryn
> >
> > >>> "Jeremy Miles" < [log in to unmask]> 22/03/2007 21:08:20
>>>
> > On 22/03/07, Kathryn Jane Gardner <[log in to unmask]> wrote:
> > > Thanks again Jeremy.
> > >
> > > In answer to your question about whether I'd claim a null result
> > with
> > > means in the wrong direction, the answer is no. In my current
> > research I
> > > have taken to approach of not running a t-test on groups with
means
> > in
> > > the wrong direction, but then commented that say males scored
higher
> > > than females, thus, no further statistical analysis was
conducted.
> > Then
> > > I have briefly discussed this finding the discussion (but only
in
> > the
> > > context of mean scores and not statistical sig., obviously). Do
you
> > > agree with this approach (given a 1 tailed test)? I suppose
ideally
> > you
> > > are saying use 2 tailed tests, which I assume would address this
> > > problem.
> > >
> >
> > Well, if you're going to do that (and you've proved that you're
doing
> > that), then I guess it's OK. But if I were meta-analysing the
data,
> > I'd be sad.
> >
> > > I like your definition of conditions for a 1 tailed test. Why
wasn't
> > > this given out to me years ago at undergrad level? Just out of
> > interest,
> > > do you have a text reference for this kind of approach to
defining 1
> > > tailed tests? I'd like to read more as none of my books or
hundreds
> > of
> > > stats papers seem to adopt this approach and google also fails
me
> > :-(
> > > Nothing like a bit of bed time stats reading, though I have to
admit
> > I
> > > like stats (shall I lock my doors now? :-)
> > >
> >
> > Abelson covers it, I think, in his book 'statistics as principled
> > argument'.
> >
> > > I don't know Patrick McGhee (he must've left the dept a while
back)
> > > though the name rings a bell. I've been at UCLan nearly 6 years
now
> > and
> > > don't recall him being a staff member. But then you finished your
PhD
> > a
> > > while back didn't you.
> > >
> >
> > He's something important like assistant vice-chancellor. I don't
> > think he's ever been in the psychology department. (I did my PhD
at
> > Derby, when he was HoD). (In 1999, if anyone's interested.)
> >
> > Jeremy
> >
> >
> >
> > > Kathryn
> > >
> > >
> > > >>> Jeremy Miles < [log in to unmask]> 22/03/2007 20:38:46
>>>
> > > On 22/03/07, Kathryn Jane Gardner <[log in to unmask]> wrote:
> > > > Thanks Jeremy for answering my questions. Just to clarify
though,
> > I
> > > was
> > > > using directional to refer to 1 tailed tests (slip in
terminology
> > as
> > > I
> > > > realise that these aren't necessarily the same thing, though
they
> > > are
> > > > often used synonymously). Someone in my dept said that if you
run
> > a
> > > 1
> > > > tailed test (say a t test) and the means in are in the wrong
> > > direction,
> > > > then the t test shouldn't be run i.e., you inspect the group
means
> > > first
> > > > and then only run t tests if results are in the direction you
> > > predicted.
> > > > I think approach is consistent with what you were saying about
not
> > > > reporting a sig result if it is in the wrong direction. I
think?
> > > >
> > >
> > > That's true, but if the means are in the wrong direction, would
you
> > > *really* say that you have found nothing.
> > >
> > > Let's say that you do a test of intelligence on black and white
> > > children. All the evidence (that I know of) would suggest that,
if
> > > you find a difference, it would be that the black children
should
> > > score lower.
> > >
> > > So you run the test, and you find that the black children score
> > > significantly higher. Do you then say "Well, that's a null
result.
> > I
> > > found no effect."?
> > >
> > >
> > > > I do see your point re: 1 tailed tests, and you clearly don't
see
> > a
> > > lot
> > > > of them in the papers you review. You said "You can make a
> > > directional
> > > > prediction based on anything. But if you then use that
> > directional
> > > > prediction to argue that you can do a one tailed test, then
that's
> > > (in
> > > > my opinion) naughty." I think like many, I have assumed that a
1
> > > tailed
> > > > test is used when a directional prediction is made and there
is
> > > enough
> > > > theory and/or evidence to do so. But it seems you don't agree
with
> > > this
> > > > and do not advocate using 1 tailed tests. As I said earlier, I
> > > haven't
> > > > come across the use of 2 tailed tests for directional
predictions.
> > > Maybe
> > > > I am missing the basic underlying principles of the use of 1
and 2
> > > > tailed tests and how they differ from directional and
> > > non-directional
> > > > tests, but if am then so are many of my colleagues! So...if
you
> > > could
> > > > define the conditions for a 1 tailed test to be run, what
would
> > they
> > > > be?
> > > >
> > >
> > > A one tailed test should be used when an effect in the opposite
> > > direction to that which was expected would theoretically
equivalent
> > to
> > > a zero effect.
> > >
> > > Jeremy
> > >
> > > P.S. Do you know Patrick McGhee, at UCLAN? He was my PhD
> > supervisor.
> > >
> > >
> > >
> > >
> > > --
> > > Jeremy Miles
> > > Learning statistics blog:
> www.jeremymiles.co.uk/learningstats
> > >
> >
> >
> > --
> > Jeremy Miles
> > Learning statistics blog:
> www.jeremymiles.co.uk/learningstats
> >
>
>
>
> --
> Leah Quinlivan
--
Jeremy Miles
Learning statistics blog: www.jeremymiles.co.uk/learningstats
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