Can anyone help with good resources on the web, journals, books, etc on
cluster analysis - simularity and ordination. Any recommended programs
for this type of analysis too.
Cheers
Elisa Wood
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On Mon, 10 Apr 2000, Rich Ulrich wrote:
-- >8 ---
> > the term 'null' means a hypothesis that is the straw dog case ... for which
> > we are hoping that sample data will allow us to NULLIFY ...
>
> - this seemed okay in the first sentence. However, I t
- Original Message -
From: Michael Granaas <[EMAIL PROTECTED]>
> Our current verbal lables leave much to be
desired.> > Depending on who you ask the "null hypothesis"
is> > a) a hypothesis of no effect (nil hypothesis)> b) an
a priori false hypothesis to be rejected (straw dog hypo
the logic behind the null hypothesis method is flawed ... IF you are
looking for truth AND you keep following the logic of testing AGAINST a
null ...
first, say you reject the null of rho = 0 ...
then, LOGICALLY ... this says that since we don't know what truth is ...
just what we think it is
Just because Dennis has trouble with the null hypothesis, that does
not mean that it is a bad idea to use them.
On 10 Apr 2000 08:41:06 -0700, [EMAIL PROTECTED] (dennis roberts)
wrote:
> the term 'null' does NOT mean 0 (zero) ... though it is misconstrued that way
>
> the term 'null' means a hy
here are a few (fastly found i admit) urls about scientific method ... some
are quite interesting
http://dharma-haven.org/science/myth-of-scientific-method.htm#Overview
http://teacher.nsrl.rochester.edu/phy_labs/AppendixE/AppendixE.html
http://idt.net/~nelsonb/bridgman.html
http://www.brint.c
My comments are about half-way down.
Michael
On Mon, 10 Apr 2000, Robert Dawson wrote:
> Dennis Roberts wrote:
>
> > now we get to the crux of the matter ... WHY do we need a null ... or any
> > hypothesis ... (credible and/or sensible) to test??? what is the
> scientific
> > need for this? w
At 01:56 PM 4/10/00 -0400, Donald F. Burrill wrote:
>On Mon, 10 Apr 2000, dennis roberts wrote in part:
>
> > .. the fact that we create a null and test a null does NOT imply that
> > we are therefore testing some effect size ...
>
>Of course not. One does not TEST an effect size, one ESTIMATES
The free ARC software from the University of Minnesota will do some of this.
Look at
http://stat.umn.edu/ARCHIVES/archives.html
Jon Cryer
At 01:59 PM 4/10/00 -0500, you wrote:
>
>Hello all,
>
>I'm looking for software that can display a 3-D regression environment (x,
>y, and z variables) and dr
On Mon, 10 Apr 2000, dennis roberts wrote in part:
> .. the fact that we create a null and test a null does NOT imply that
> we are therefore testing some effect size ...
Of course not. One does not TEST an effect size, one ESTIMATES it.
And it is useful to do so only if one has found it not
Wouldn't you learn the same thing with a confidence interval on rho?
Jon Cryer
At 02:19 PM 4/10/00 -0400, you wrote:
>Seems to me that hypothesis testing remains an essential step. Take for
>instance the following data that I made up just for the purpose of
>illustration and the correlation matr
On Mon, 10 Apr 2000, Robert Dawson wrote:
> Michael Granaas wrote:
>
> H0: being in the target population has no effect on sexual dimorphism in
> height
> Ha: being in the target population does affect sexual dimorphism in
> height
I want to see if I am interpreting your meaning correct
Hello all,
I'm looking for software that can display a 3-D regression environment (x,
y, and z variables) and draw a regression plane for each of two subgroups.
So far, Minitab does a good job of the 3-D scatterplots (regular,
wireframe, and surface (plane) plots), but there's no option (as in
Michael Granaas wrote:
> In one case we can do that mathematically by rearranging a hypothesis of
> (mu1 - mu2 = 3) to the form ((mu1 - mu2) - 3 = 0). If this is what Robert
> means by saying that only no effect hypotheses are meaningful I think we
> are in partial agreement. I personally shudd
Seems to me that hypothesis testing remains an essential step. Take for
instance the following data that I made up just for the purpose of
illustration and the correlation matrix it produces:
VAR1 VAR2
2.002.00
3.002.00
5.006.00
4.002.00
3.001.00
Correlations
Dennis Roberts wrote:
> now we get to the crux of the matter ... WHY do we need a null ... or any
> hypothesis ... (credible and/or sensible) to test??? what is the
scientific
> need for this? what is the rationale within statistical exploration for
this?
My understanding, not perhaps parall
I, and I think Dennis, are arguing that when we test a hypothesis we
should have a null hypothesis that is plausibly true. A hypothesis that
reflects some sort of an effect size estimate where such an estimate is
meaningful.
If I understand correctly Robert is arguing that we should always phra
At 01:16 PM 4/10/00 -0300, Robert Dawson wrote:
>both leave the listener wondering "why 0.5?" If the only answer is "well,
>it was a round number close enough to x bar [or "to my guesstimate before
>the experiment"] not to seem silly, but far enough away that I thought I
>could reject it." then
At 01:16 PM 4/10/00 -0300, Robert Dawson wrote:
> No if you have to start "a more sensible null would be perhaps" you
>almost surely do not have a hypothesis worth testing.
now we get to the crux of the matter ... WHY do we need a null ... or any
hypothesis ... (credible and/or sensibl
I am new to the list so I am jumping into the middle of this. However, we
have to start teaching hypothesis testing somewhere. Even if it goes the
way of the Edsel, it will be a slow death because many of us will continue
to use when we feel it is appropriate to the question. However, I tell my
st
Michael Granaas wrote:
> My grandmother could have told me that the mean height for men and women
> was not the same (zero difference). So based on prior evidence I
> hypothesize that the actual difference is 3 inches (mu1 - mu2 = 3) and use
> that for my null hypothesis. True, I can reduce thi
Dennis Roberts wrote:
> if you are interested in the relationship between heights and weights of
> people, in the larger population ... the notion that we test this against
a
> null of rho=0 is not credible ... in fact, it is rather stupid ... a more
> sensible null would be perhaps a rho of .5 .
At 12:44 PM 4/10/00 -0300, Robert Dawson wrote:
> Moreover, in cases in which the null
>hypothesis has any prior credibility - as should always be the case - that
>"something" (eg, amount by which the IQ of the subject population differs
>from the standardized value of 100) is usually a sensible
On Mon, 10 Apr 2000, Robert Dawson wrote:
> Dennis Roberts wrote:
>
> > the term 'null' does NOT mean 0 (zero) ... though it is misconstrued that
> way
> > the term 'null' means a hypothesis that is the straw dog case ... for
> which
> > we are hoping that sample data will allow us to NULLIFY ..
On Mon, 10 Apr 2000, dennis roberts wrote:
> the term 'null' does NOT mean 0 (zero) ... though it is misconstrued that way
Yes, and yes. I tend to switch to "nil" hypothesis to indicate that
special case of the null.
>
> the term 'null' means a hypothesis that is the straw dog case ... for wh
Dennis Roberts wrote:
> the term 'null' does NOT mean 0 (zero) ... though it is misconstrued that
way
> the term 'null' means a hypothesis that is the straw dog case ... for
which
> we are hoping that sample data will allow us to NULLIFY ...
> in some cases, the null happens to be 0 ... but in ma
In thinking about my own failure to get students to ask follow up
questions to a null hypothesis test I have formulated a couple of possible
reasons. Let me know what you think.
1. Even when we teach statistics in the discipline areas we fail to
integrate it with research. We teach a course in
the term 'null' does NOT mean 0 (zero) ... though it is misconstrued that way
the term 'null' means a hypothesis that is the straw dog case ... for which
we are hoping that sample data will allow us to NULLIFY ...
in some cases, the null happens to be 0 ... but in many cases, it does not
cases
Bruce Weaver wrote (in part):
...Negative priming is measured as a response time
> difference between 2 conditions in an experiment. The difference is
> typically between about 20 and 40 milliseconds...
> The researcher KNOWS that a lot of other things affect
> respons
On Fri, 7 Apr 2000, dennis roberts wrote:
> At 04:00 PM 4/7/00 -0500, Michael Granaas wrote:
>
> >But whatever form hypothesis testing takes it must first and formost be
> >viewed in the context of the question being asked.
>
>
> this seems to be the key to REinventing ourselves ... make sure
On 7 Apr 2000, dennis roberts wrote:
> i was not suggesting taking away from our arsenal of tricks ... but, since
> i was one of those old guys too ... i am wondering if we were mostly lead
> astray ...?
>
> the more i work with statistical methods, the less i see any meaningful (at
> the lev
On Fri, 7 Apr 2000, Chris Mecklin wrote:
Among other things
>
> My point is that I want to show my class an example where they can see the
> pitfalls of making a decision based solely on a p-value. I don't want
My favorite, not contrived example, has to do with vocational advice and
gender. I
Dennis Roberts asked, imagining a testing-free universe:
>> what would the vast majority of folks who either do inferential work
>and/or
>> teach it ... DO
>> what analyses would they be doing? what would they be teaching?
I wrote:
> >* students would be told in their compulsory intro stats
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