HDTenEightyP/NetNews huggingface dataset:
Newsgroups: bit.listserv.linkfail
Date:         Fri, 9 Oct 1992 14:02:26 MEZ
Reply-To:     Erwin Halpern <EARNADM@AWIUNI11.BITNET>
From:         Erwin Halpern <EARNADM@AWIUNI11.BITNET>
Subject:      Vienna/AT problems
Comments: To: pits@Princeton.EDU
Comments: cc: Ewald Jenisch <z00ejr01@AWIUNI11.BITNET>

Attention:

We are currently switching the IP-line LINZ-VIENNA from a 64KB-line
to a 128KB line. Some interruptions may occur on EARN-links from
AEARN(LINZ) to all AWIxxxxx(VIENNA) nodes.

Service should be ok again at around 15:00 UTC.

Sorry for any inconveniences.

Erwin Halpern
Comments: Gated by NETNEWS@AUVM.AMERICAN.EDU
X-VMS-To: @[NIC.TICKET]sara-cern
Newsgroups: bit.listserv.linkfail
Date:         Wed, 7 Oct 1992 11:43:00 MET
Reply-To:     "SARA Network Information Centre" <NIC@SARA.NL>
From:         "SARA Network Information Centre" <NIC@SARA.NL>
Subject:      TICKET [.sara-cern]921007-2 CLOSE
Comments: To: eot@ebone.net, ic@sara.nl, netmaster@surfnet.nl, saranet@sara.nl,
              sn-ipman@nic.surfnet.nl, ripe-op@ripe.net

Ticket Number: [.sara-cern]921007-2  Ticket Status:   close
Ticket Type:   scheduled             Ticket Source:   SARA
Ticket Scope:  router                Site/Line:       Amsterdam-EBS1
Ticket Owner:  nic@sara.nl           Problem Fixer:   SARA

Ticket Opened: 921007 11:34 CET      Problem Started: 921019 18:00 CET
       Closed: 921007 11:41 CET                Ended: 921019 22:00 CET


Problem Description:
        Because of maintenance, the Amsterdam-EBS1 router will be switched off
        for a short while.

Affected:
        IP traffic between northern and southern Europe and USA.
        Also affected: EARN traffic.

Actions:


Time to fix:
        A few minutes (we hope).
Fix:
Comments: Gated by NETNEWS@AUVM.AMERICAN.EDU
Newsgroups: bit.listserv.linkfail
Date:         Mon, 12 Oct 1992 09:07:11 MEZ
Reply-To:     Erwin Halpern <EARNADM@AWIUNI11.BITNET>
From:         Erwin Halpern <EARNADM@AWIUNI11.BITNET>
Subject:      AT-problems
Comments: To: pits@Princeton.EDU
Comments: cc: Ewald Jenisch <z00ejr01@AWIUNI11.BITNET>

Hello again,

I am sorry that I have to announce that the problems with the new lines
(128KB Vienna-Linz and 256KB Vienna-Geneva) still haven't been solved.

We are working on that and so traffic (EARN and IP) may be interrupted
repeatedly between 10:00 UTC and 14:00 UTC.

Hopefully we can fix the problems quick.

Sorry for any inconveniences.

Erwin Halpern
Comments: Gated by NETNEWS@AUVM.AMERICAN.EDU
Original_To:  @AUVM,@USGS,JNET%"linkfail@bitnic"
Original_cc:  HOLT
Newsgroups: bit.listserv.linkfail
Date:         Sat, 10 Oct 1992 11:33:00 EST
Reply-To:     "Tracy S. Holt" <HOLT@GMUVAX.BITNET>
From:         "Tracy S. Holt" <HOLT@GMUVAX.BITNET>
Subject:      GMU Scheduled Dowtime, 10/11/92 6am-10am

GMUVAX will be UNAVAILABLE from 6:00am - 10:00am on Sunday, October 11,
due to a scheduled power outage. During this downtime, USGSRESV will also
be unreachable.

Tracy S. Holt
GMU
Computer Systems Engineering
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Newsgroups: bit.listserv.linkfail
Date:         Fri, 9 Oct 1992 16:45:55 MET
Reply-To:     Daniele Vannozzi <VANNOZZI@VM.CNUCE.CNR.IT>
From:         Daniele Vannozzi <VANNOZZI@VM.CNUCE.CNR.IT>
Subject:      ICNUCEVM / CNUCE downtime
Comments: To: PITS@PRINCETON.EDU

ICNUCEVM downtime: From October, 17th (Saturday), 02:00 a.m. local time
                   to   October, 17th (Saturday), 18:00 p.m. local time

REASON: Power maintenance

AFFECTED NODE(S):  all Italian EARN nodes

AFFECTED INTERNATIONAL LINK(S): CEARN, UICVM, FRMOP11, DEARN, HEARN,
                                AEARN, TAUNIVM, SEARN, UKACRL

Daniele Vannozzi             Phone:  +39 50 593280
CNUCE - Istituto del CNR     Fax:    +39 50 589354
Via Santa Maria 36           Telex:  500371 - CNUCE
56100 Pisa - Italy           E-mail: vannozzi@vm.cnuce.cnr.it
Comments: Gated by NETNEWS@AUVM.AMERICAN.EDU
Newsgroups: bit.listserv.linkfail
Date:         Fri, 9 Oct 1992 16:25:30 EDT
Reply-To:     Helen McLean <HLMCU@CUNYVM.BITNET>
From:         Helen McLean <HLMCU@CUNYVM.BITNET>
Subject:      CUNYVM system unavailability 10/12/92

All CUNYVM nodes (CUNYVM, CUNYVMV2, and CUNYVM.CUNY.EDU) will be
unavailable Monday, October 12, 1992, between 8:00 a.m. and 2:00 p.m.
(Eastern Daylight Time) due to hardware maintenance. CUNYJES3 will be
unavailable 10:00 a.m. to 8:00 p.m., due to system maintenance.
Comments: Gated by NETNEWS@AUVM.AMERICAN.EDU
Newsgroups: bit.listserv.linkfail
Date:         Tue, 13 Oct 1992 12:45:40 MEZ
Reply-To:     Erwin Halpern <EARNADM@AWIUNI11.BITNET>
From:         Erwin Halpern <EARNADM@AWIUNI11.BITNET>
Subject:      AT problems
Comments: To: pits@Princeton.EDU

Sorry to annonce that we have still problems with our new line
128KB Vienna-Linz. So currently the EARN-nodes in Vienna are
unreachable. Problem should be solved today afternoon.

Glad to announce:

New 256KB Geneva-Vienna is up and running. It has been considered as
STABLE.

Erwin
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Newsgroups: bit.listserv.stat-l
Date:         Thu, 8 Oct 1992 15:30:11 -0400
From:         AL BEST <BEST@VCUVAX.BITNET>
Subject:      Designed Experiments Texts

Please,
   I'd like your recommendation as to the best one or two
texts that meet the following criteria:

   1) Primary focus: Design of experiments
      (fractional factorials, etc.)
   2) LOTS of good examples for engineers, chemists, you
      know, practical folks.
   3) A realistic emphasis on the whole process of taking an
      existing process (or a new, as yet, unrealized process)
      through  the multiple stages of testing, refining your
      idea of the "important" effects, zeroing in on the facets
      of optimality, finding optimal points that are robust,
      ...  an  on.
      The emphasis should be on the word "realistic" as opposed
      to "theoretical" and on "the whole process" rather than
      acting like we do one experiment and then we're done.

Thanks,
Al Best
Virginia Commonwealth University
Richmond VA
Comments: Gated by NETNEWS@AUVM.AMERICAN.EDU
Newsgroups: bit.listserv.stat-l
Date:         Mon, 12 Oct 1992 15:56:47 CST
From:         April Milliken <BIOM030@UNLVM.BITNET>
Subject:      NEED HELP ON PCA

(Sorry...this was also sent to EDSTAT)

I need some help with a consulting problem...I lack in experience (I am a
grad student) and so I would like to hear from "experts".

I am working with a professor in animal science kindly named "Mr. Means".
He wants to publish correct results, but he seems to have difficulties in
understanding anything beyond one-way anovas.  Consequently, I have two
problems:

1)  The data are biochemical results; the machine (I am told) sometimes
    fails to give a correct result due to lack of solution (or whatever
    excuse).  Consequently, Mr. Means went through the data and elminated
    results that he did not feel were plausible (say a pH value that was
    higher than the rest of the values).  If they are removed, should I
    remove that observation on that animal, or remove the entire animal
    (keep in mind that only 15 animals are used in the study)?

2)  This is a perfect example of needing a principal components analysis
    in one area and repeated measures in another.  HOWEVER, this is WAY
    beyond the comprehensive power of Mr. Means.  I ran a PCA and came up
    with some insightful results...yet, I am at a loss as where to go
    from here; do I push PCA with 8 variables, or do 8 different one-way
    ANOVAs for Mr. Means?

I hope someone can help me out here.  I am at a loss....I NEED HELP!

Thanks in advance.

April Milliken
Department of Biometry
University of Nebraska-Lincoln
BIOM030@unlvm1.unl.edu

"I may be in Nebraska, but my heart belongs to Kansas State University!"
From: flim@weber.ucsd.edu (Francis Lim)
Newsgroups: bit.listserv.stat-l
Subject: Re: Data snooping
Date: 15 Oct 92 00:25:49 GMT
Organization: University of California, San Diego
NNTP-Posting-Host: weber.ucsd.edu

The economics profession has attached the term "data mining"
to what here has been called "data snooping." No difference.
A few colleagues and I like to call it "model mining" (laughter).

A colorful economics professor, David Hendry, of the London School
of Economics, likes to think of p-values of statistics obtained
from data mining more of as diagnostic values which "guide" one
in obtaining a "good" model. Valid *tests* of this model, then,
are obtained through out-of-sample testing.

Of course, in physics, relationships purportedly remain the same
in a closed system (whatever that is).
In economics, however, humans may have the tendency to change their
minds, government policy may change, etc., rendering out-of-sample
tests useless. The key question then, is ... just what is one
interested in modeling? Behavior before a structural break,
behavior after, or the structural break itself?

The thing to keep in mind (in economics) is that we always believe
that the true data generating process and our specified model of
estimation coincide with probability 0. Thus, p-values have no
real meaning in any event! But we do what we can...
-- 
==============================================================================
     FRANCIS W. LIM / email: flim@ucsd[.edu] / dept phone: (619) 534-3383
     Dept of Economics, Univ of Cal at San Diego, La Jolla, CA 92093-0508
==============================================================================
Comments: Gated by NETNEWS@AUVM.AMERICAN.EDU
Encoding: 5 TEXT
X-Mailer: Microsoft Mail V3.0 (beta-2)
Newsgroups: bit.listserv.stat-l
Date:         Sat, 10 Oct 1992 10:53:00 EST
From:         mmz1@CCDDCD1.EM.CDC.GOV
Subject:      Elementary IMPUTATION discussion?

Rubin's book on missing data may be what you're looking for but it may be too
advanced for you.

Matthew Zack
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Encoding: 19 TEXT
X-Mailer: Microsoft Mail V3.0 (beta-2)
Newsgroups: bit.listserv.stat-l
Date:         Thu, 15 Oct 1992 17:05:00 EST
From:         POSTOFFICE@ROUTER.EM.CDC.GOV
Subject:      RETURNED BY ADMINISTRATOR

>    I need to generate several random samples of size 200 to 400 from a
> normal multivariate theoretical population of which the variance-covariance
> matrix is known. The only software that would do this that I know of is
> GENRAW, a utility program distributed with Lisrel. Unfortunately, it is
 limited
> to 10 variables while the problems I am working on involve 11 and 14
 variables.
>
>    So does anyone on the list know of a software, program or big macro that
> would generate artificial random samples for up to at least 14 variables?

There has been some discussion on this topic in this list sometime ago. All
you need to do is Cholesky factorization. Almost all the statistical
packages have routines to do this. One I like is the IMSL routine RNMVN. I
don't believe there any restrictions on the number of variables.

A. Narayanan
School of Business
Indiana University
Comments: Gated by NETNEWS@AUVM.AMERICAN.EDU
Newsgroups: bit.listserv.stat-l
Date:         Tue, 13 Oct 1992 10:38:51 CET
From:         Joop Hox <A716HOX@HASARA11.BITNET>
Subject:      discarding outliers

To get back to April Milliken's question about discarding observations.
I used to do psychology experiments in my undergraduate days, and then the
rule was to discard observations only when you could prove that the apparatus
broke down at a specific measurement. There should be some evidence independent
of the value of the observation. Discarding observations because you don't like
their value was not done.

There are a number of statistical tests to test whether an outlier is
significantly different from the other observations. In my experience, this
test often tells you that an observation that you thought was an outlier is
actually consistent with the bulk of the data. I don't have the reference handy
but Vic Barnett wrote a book about detecting outliers, with all the tests and
tables you need.

Joop Hox
University of Amsterdam
Newsgroups: bit.listserv.stat-l
From: BASS%TECHDB%MISX02@KINGSTON.ARPC.ALCAN.CA (Sheryl Bass,
              ARPC Oswego. Tel. (315) 349-0198)
Newsgroups: bit.listserv.stat-l
Subject: Data snooping
Date: 15 Oct 92 16:50:00 GMT
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Content-transfer-encoding: 7BIT

>I usually discover serious design flaws and other data problems in
>the experiment.  Most problems we can work around and many of my
>"discoveries" about the data are of valuable interest to the researcher,
>but s/he would not have thought about looking for them.

>I get very dismayed when I see people blindly analyze data according to
>some canned technique without even bothering to see what they actually
>discovered.  The excitement generated from my "data snooping" is a joy
>to observe and I believe is a necessary part of research, which I
>define as "exploration".

 I couldn't agree more!!!!  But the scary thing is that almost every time
 you WILL find some flaw or another in a design or analysis. Oh well, that's
 what keeps it marginally exciting.

Sheryl Bass
From: wilkie@unixg.ubc.ca (Donald Wilkie)
Newsgroups: bit.listserv.stat-l
Subject: interesting data sets
Date: 16 Oct 1992 22:33:42 GMT
Organization: University of British Columbia, Vancouver, B.C., Canada
Distribution: na
NNTP-Posting-Host: unixg.ubc.ca
Originator: wilkie@unixg.ubc.ca

I am looking for interesting data sets of the type that appear
in Velleman & Hoaglin's ABCs of EDA text for my undergrauate
stat course. Any pointers will be appreciated. Please reply
by email. Thanks. 

Comments: Gated by NETNEWS@AUVM.AMERICAN.EDU
Via:        UK.AC.OX.MR; 16 OCT 92 14:35:10 BST
Newsgroups: bit.listserv.stat-l
Date:         Fri, 16 Oct 1992 14:33:06 +0100
From:         Brendan Halpin <halpin@VAX.OX.AC.UK>
Subject:      Re: Akaike's Info. Crit. & PROC MIXED

Clark Gaylord described Akaike's Information Criterion thus:

> For the "bigger is better" version of AIC:
>    -2*ln(like) -- the bigger the better, right?  But, in general gets
>                   large (inappropriately from Akaike's viewpoint) as p
>                   increases.
>     2*p        -- this is our "penalty" term, to take away some of the
>                   "natural growth" that -2*ln(like) has for large p.
> Hence:
>    AIC = -2*ln(like) - 2*p
>
> I will not comment much on the appropriateness of this measure, though I
> think it is fair to say that the jury is still out regarding its usefulness.

This sounds to me a lot like Adrian Raftery's BIC statistic.
Quoting Yu Xie, "for large samples: BIC = L2 - (df)logN, where L2
is the log-likelihood ratio statistic, df is the associated degrees
of freedom, and N is the sample size". This is often used --
recently, at any rate -- in log-linear and log-multiplicative
models. However, the "jury is out" on this one too, with (in the
field I know anything about) people like John Goldthorpe and Robert
Erikson claiming it leads to excessively parsimonious models,
countered by Raftery, Mike Hout, Xie and others who argue for its
validity.

The reason I'm posting this is (a) to ask for comments on the
relationship between AIC and BIC (it's outside my mathematical
competence to do it myself) and (b) to solicit opinions on the
validity and usefulness of BIC itself.


Refs:
Adrian Raftery (1986) `Choosing models for cross-classifications
   (Comments on Grusky and Hauser)', Am. Soc. Rev. 51.
Michael Hout (1989) _Following in Father's Footsteps_, Harvard UP
Yu Xie (1992) `The log-multiplicative layer effect model for
   comparing mobility tables', Am. Soc. Rev. 57.


Brendan

Brendan Halpin                    Email: HALPIN@VAX.OXFORD.AC.UK
Nuffield College                  Phone: +44 865 278642
Oxford OX1 1NF
United Kingdom
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X-Vms-Mail-To: @STAT-L
Newsgroups: bit.listserv.stat-l
Date:         Tue, 13 Oct 1992 08:55:41 EST
From:         dixon@SREL.EDU
Subject:      Proving no difference

Andy Taylor asks about statistical methods to "prove" the absence of
a difference or effect.  It is extemely unlikely that the difference
between two population means (or any other parameter of your choice)
is exactly zero.  Hence, a sufficiently large experiment is likely
to reject any point hypothesis.

An alternative is to consider hypotheses of the form:
  abs(mu1 - mu2) < c
Tests based on hypotheses of this form are called bioequivalence
tests in the pharmaceutical literature.  In the typical bioequivalence
setup, the null hypothesis: abs(mu1-mu2) > c is tested.  If rejected,
then two groups are considered to be similar in effect, relative to the
critical difference c.  A common application is whether generic drugs
have similar efficacy as the brand-name.
I haven't kept up with the most recent developments in bioequivalence,
but some papers are:
Westlake, W.J. 1988, Bioavailability and bioequivalence of
  pharmaceutical formulations.  In Peace, K.  Biopharmaceutical statistics
  for drug development.  Marcel Dekker
Hauck, W.W. and Anderson, S. 1984.  A new statistical procedure for
  testing equivalence in two-group comparative bioavailability studies
  J. Parm. Biopharm.  12:83-91
Kirkwood, T.B.L. 1981.  Bioequivalence testing - a need to rethink
  Biometrics 37:589-594

We discuss this and some related issues from the standpoint of toxicological
field experiments in:
Dixon, P.M. and Garrett, K.A. Statistical Issues for Field Experimenters
  In Lacher, T (ed.) New Approaches in Wildlife Toxicology.  SETAC Press
This should be published imminently, over 2 years after the papers were
submitted.

Philip Dixon, dixon@srel.edu
From: ILFC594@VAX2.CONCORDIA.CA (GEOFF SELIG - CONCORDIA U. COMPUTING SERVICES)
Newsgroups: bit.listserv.stat-l
Subject: Data snooping and hypothesis tests
Date: 15 Oct 92 19:56:00 GMT
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X-Organization: Concordia University, Montreal, Quebec
X-Envelope-to: stat-l@MCGILL1.BITNET
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X-VMS-Cc: ILFC594

Andy Taylor writes:
 > [note from Pgil Gallagher regarding deriving hypotheses to be tested
 >  from descriptive statistics and graphs]
 > This seems like flagrant data snooping. How can you come up with tests or
 > estimates that take into account that you first looked through the data,
 > then decided what (and how) to do inference about? To put it another way,
 > if you don't think the data are up to being analyzed formally, why not just
 > show the pictures and stop at that?

Assuming that appropriate inferential statistics are performed, what Phil
is suggesting is perfectly valid.  In general, the tests that could be
performed would have to fit under the umbrella term _post hoc_ multiple
comparisons.  Data snooping _does_ imply that a great many possible tests
will not be made because they "don't look significant."  This could lead to
an under-estimation of the type I error rate.  However, when handled
sensibly using the appropriate statistical techniques, such an approach is
very productive and informative.

Geoff Selig        Phone (514)-848-7666 |        _,  /|     The Cat's Meow
Academic Services    FAX (514)-848-7622 |        \ o.O'
Department of Computing Services        |        =(___)=
Concordia University   (H928)           |            U
Montreal, Quebec   H3G 1M8              |  ilfc594@vax2.concordia.ca
                                        |  ilfc594@conu2.BITNET
From: ILFC594@VAX2.CONCORDIA.CA (GEOFF SELIG - CONCORDIA U. COMPUTING SERVICES)
Newsgroups: bit.listserv.stat-l
Subject: Independence of observations in logistic regression
Date: 9 Oct 92 17:39:00 GMT
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X-Organization: Concordia University, Montreal, Quebec
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A researcher in the Education department at Concordia University has
collected observational data on children in a variety of school settings.
There are often several observations taken on each child, so one cannot
assume independence of observations which, I have been taught, is a
requirement for multiple regression and, I would assume, logistic
regression as well.  The researcher has run logistic regressions and has
been queried by a reviewer as to the implications of non-independence on
the analyses.

I would appreciate a nudge in the right direction (a reference or a short
comment) that would help me understand and help this researcher's need to
repond to the reviewer.

Geoff Selig        Phone (514)-848-7666 |        _,  /|     The Cat's Meow
Academic Services    FAX (514)-848-7622 |        \ o.O'
Department of Computing Services        |        =(___)=
Concordia University   (H928)           |            U
Montreal, Quebec   H3G 1M8              |  ilfc594@vax2.concordia.ca
                                        |  ilfc594@conu2.BITNET
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Newsgroups: bit.listserv.stat-l
Date:         Fri, 9 Oct 1992 16:05:04 -0500
From:         MGRANAAS@CHARLIE.USD.EDU
Subject:      Another logistic reg questions

Hello,

I have some data which I believe are appropriate for analysis with
logistic regression.  However, the only references I can find rummaging
around in my office are the occasional chapters on dicotomous logistic
regression.  From these descriptions, I believe that logistic regression
is what I'm looking for, but I have to learn more.  Specifically, I need
to learn about logistic regression when I have a polycotomous variable
to predict.   Any suggestions on references?

TIA
Mike Granaas
mgranaas@charlie.usd.edu
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Newsgroups: bit.listserv.stat-l
Date:         Wed, 7 Oct 1992 11:45:06 EDT
From:         "(Laplante Benoit)" <laplante@ERE.UMONTREAL.CA>
Subject:      Var(A*B)

   Last week, someone asked a question that started a discussion on the
variances of product of variables. I didn't pay much attention to the
original question but got interested in a reply by Dick Darlington that
more directly addressed something I was looking for at the same time.
I finally foud three references on the matter that may be of interest to those
who took part in the original discussion and, following Dick's suggestion, here
they are for the benefit of all.

BOHRNSTEDT, G.W. and GOLDBERGER, A.S. (1969) "On the exact covariance of
products of random variables", Journal of the American Statistical Association,
64:1439-1442.

GOODMAN, L.A. (1960) "On the exact variance of products", JASA, 55:708-713.

GOODMAN, L.A. (1962) "The variance of the products of k random variables", JASA
57:54-60.

Benoit Laplante
Departement de psychologie
Universite de Montreal
Laplante@ERE.UMontreal.CA
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Newsgroups: bit.listserv.stat-l
Date:         Fri, 9 Oct 1992 15:34:00 EDT
Comments:     208 Cedar Bldg.
Comments:     University Park, PA USA
Comments:     AC 814-863-2401
From:         Dennis Roberts <DMR@PSUVM.BITNET>
Subject:      Re: Independence of observations in logistic regression

Usually, in multiple regression, the situation is that you have numerous
variates on the SAME objects; how else will you get the data?  Thus, there
is no problem in looking at the multiple regressiion of several predictors
on some criterion.  Data are naturally correlated in this situation; ie,
they are not independent.  True, there would be a higher multiple R if the
predictors correlated 0 but, all that means is that combining correlated
variables does not gain you as much as combining uncorrelated variables.  In
either case, R is appropriate.