Anonymous God-fearer <[EMAIL PROTECTED]> wrote:
> Does anyone know how to generate a correlation matrix given a covariance
> matrix in Splus?
> Or could you give the details of how to do it in another language?
corr[i,j] = cov[i,j]/sqrt(cov[i,i]*cov[j,j])
===
Rolf Dalin <[EMAIL PROTECTED]> wrote:
> Brad Anderson wrote:
>> I have a continuous response variable that ranges from 0 to 750. I only
>> have 90 observations and 26 are at the lower limit of 0,
> What if you treated the information collected by that variable as really
> two variables, one ca
John Kane <[EMAIL PROTECTED]> wrote:
> Dennis Roberts wrote:
>> At 08:56 AM 11/16/01 -0700, Roy St Laurent wrote:
>> >It's not clear to me whether recent posters are serious about these
>> >examples, but
>> >I will reiterate my previous post:
>> >
>> >For most mathematics / statistics examination
Ivan Balducci <[EMAIL PROTECTED]> wrote:
> I would like to understand the meaning of negative Cohen´s Kappa value
> (1960). I got it from the following data (from Dental Radiology):
> Magnetic resonance versusFacial Pain Total
>Yes
Dennis Roberts <[EMAIL PROTECTED]> wrote:
> if we take the infamous #39 item ... where the options were (if i recall)...
> A. mean only
> B. median only
> C. range and mean
> D. range and median
> well, even if we accepted this item as "fair" ...
> a student looks at the graph ... sees that th
Robert J. MacG. Dawson <[EMAIL PROTECTED]> wrote:
> If indeed the scores are being reduced by hiding the easy questions
> among the harder ones, then I would say yes, this is a defect of the
> current system, and should be changed. It may be that the questions
> themselves ought to be more d
In sci.stat.consult Graeme Byrne <[EMAIL PROTECTED]> wrote:
> In short, you don't. If the number of terms in the model equals the number
> of observations you have much bigger problems than not being able to compute
> adjusted R^2. It should always be the case that the number of observations
> exc
jim clark <[EMAIL PROTECTED]> wrote:
> "Chebyshev's Theorem: For any positive constant 'k', the
> probability that a random variable will take on a value within k
> standard deviations of the mean is at least 1 - 1/k2 ."
> This theorem holds for any distribution.
If you know that the distributi
Philip Ackerman <[EMAIL PROTECTED]> wrote:
> Hello,
>I have a question regarding the term "independent, identically
> distributed" random variables. For example, suppose that your random
> variable is height, and the population of interest is adult males. You take
> a sample (size n) of adul
Dennis Roberts <[EMAIL PROTECTED]> wrote:
> inherent problems related to LICKert items and level of measurement that
> create problems would be these too
> 1. how many response categories are there for AN item??? by the way ...
> likert used many types ... including YES ? NO
> at THIS level ..
Robert J. MacG. Dawson <[EMAIL PROTECTED]> wrote:
> Therefore, I would not expect regression to the mean to be sufficient
> to explain the observed outcome (in which "practically no" top schools
> met expectations); and I conclude that the goals may well have been
> otherwise unreasonable. I
In sci.stat.edu Ronald Bloom <[EMAIL PROTECTED]> wrote:
> So far, NOT ONE person here has responded to my
> point that the likelihood of getting into a tangle
> of some sort with a machine or mechanical procedure
> of some kind does not necessarily have anything
> to do with one's level of literac
Ronald Bloom <[EMAIL PROTECTED]> wrote:
> Would the group of kids doing a post-hoc experiment be
> biased inasmuch as the nature of the problem at hand may
> have become common-knowledge by now; even among kids; and
> so one would be forewarned of the error-mode in question,
> and be much less l
Reg Jordan <[EMAIL PROTECTED]> wrote:
> It's interesting that no Republicans have claimed that the ballot was misleading --
>all the complaints seem to come from Democrats. Wouldn't the "misleading, confusing"
>nature of the ballot apply equally across the voting spectrum?
Bush's name and hole
Herman Rubin <[EMAIL PROTECTED]> wrote:
> As we get more complex situations, like those happening
> in biology, and especially in the social sciences, it is
> necessary to consider that models may have substantial
> errors and still be "accepted", as one can only get some
> understanding by using
dennis roberts <[EMAIL PROTECTED]> wrote:
> At 06:14 AM 10/21/00 +0000, Eric Bohlman wrote:
>>
>>1) It demonstrates that a correlation problem in which one variable is
>>dichotomous is equivalent to a two-group mean-difference problem.
> maybe you can make this p
[EMAIL PROTECTED] wrote:
> Two probability questions...
> If X has chi-square distribution with 5 degrees of freedom
> 1. what is the probability of X > 3
Look that value up in a chi-square table and find out.
> 2. what is the probability of X > 3 given that X > 1.1
Look both values up in a
dennis roberts <[EMAIL PROTECTED]> wrote:
[regarding the "point biserial correlation"]
> and it certainly has nothing to do with a "shortcut" formula for
> calculating r ... it MAY have decades ago but it has not for the past
> 20 years ...
While I certainly agree that many textbooks conv
Karl L. Wuensch <[EMAIL PROTECTED]> wrote:
> I think that Bob Hayden is on to something essential here ("I noted that
> Karl presented all the understandings he sought verbally on the list. Why
> not do the same in class?"). I think of the "definitional formulae" just as
> a convenient shorthand
Mike Hewitt ([EMAIL PROTECTED]) wrote:
: I am looking for assistance in interpreting results of a study. It
: involved the testing of three different music practicing conditions. I
: performed a GLM-repeated measures with three factors (modeling,
: self-listening, self-evaluation) in addition to
Robert J. MacG. Dawson ([EMAIL PROTECTED]) wrote:
: I would argue that for _most_ questions it is _a_priori_ plausible that
: the outcome correlates significantly with the probability of response.
: Recall the famous self-selected survey done by (Ann Landers/Dear Abby)
: in which readers wit
Milo Schield ([EMAIL PROTECTED]) wrote:
: What kinds of questions or exercises (either abstract or particular) would
: be good ways of measuring a student's understanding of conditional
: probability?
"Court records indicate that 66% of persons convicted of crimes in
Hoogledash Country are black
Robert Dawson ([EMAIL PROTECTED]) wrote:
: Well, yes, there are; there is no easy way to pass on a reference
: any more. It is aggravating when you want to send somebody the URL for
: one page in a big site and it is a frame on a huge page, so that the
: URL gets you only to the "home frame".
[EMAIL PROTECTED] wrote:
: had forgotten what a p-value is. I find it helpful to explain
: significance tests and the outcome of a study
: as follows:
:
: The difference is either
:
: Statistically significant and big enough to be of practical importance.
: Statistically not significant and
Robert McGrath ([EMAIL PROTECTED]) wrote:
:
: If what you mean is that really large samples can lead to distorted
: results of significance tests, I would disagree. The problem is not
: that the sample is too big, but that Significance tests are interpreted in
: inappropritae ways when readers as
Richard A. Beldin, Ph.D. ([EMAIL PROTECTED]) wrote:
: When my students asked me (as a class) to grade on a curve, I suggested the
: following alternative.
: "Place N chips in a can. Let them marked in the following way: 10%F, 20%D, 40%C,
: 20%B, 10%A. Let each student pick a chip and leave the cla
David A. Heiser ([EMAIL PROTECTED]) wrote:
: Demming sounds like Karl Marx. In an ideal enlightened society Demmings
: approach would work. However the ideal enlightened society always comes
: apart because of greed.
If you say that Deming sounds like Karl Marx, it means only one thing:
that you
Michael Granaas ([EMAIL PROTECTED]) wrote:
: While more careful admissions processes would certainly limit the
: variability in students, and therefor grading, how is it any different
: from grading? If you are going to be more careful with admissions you
: need a ranking system of some sort to d
EAKIN MARK E ([EMAIL PROTECTED]) wrote:
: While I do not grade on a curve, I feel that if reasons exist,it is more
: valid to adjust atypical grades distributions than not to adjust them.
: My reason for not grading on a curve is more for class harmony. Grading on
: a curve often means taking poi
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