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#1755 From: aylin alin <aktanayl@...>
Date:: Mon Oct 2, 2006 3:11 pm
Subject:: Re: Difference B/W Logstic and Log-linear models
aktanayl
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Hi there,
 
I dont know if you get any answer to your question but I just saw your question and will try to give some explanation.
 
Log-linear models are used to model expected frequencies or probabilities in contingency tables without distinguishing between independent and dependent variables. It is used for modelling categorical variables. In summary you model the counts in contingency tables and make inferences about the main effects or interaction effcets of categorical variables in contingency tables.
 
Logistic regression, on the contrary, is used for modeling dichotomuous categorical or ordered varaiables. In that case you have dependent variable which may be dichotomuous categorical variable or ordered variable. Independent variables may be both categorical or continuous.
 
These are the basic differences between two models. I hope those helps.
 
Best
Aylin

vrajak_msu <vrajak_msu@...> wrote:
dear friends
can any body give me a simple idea about Logstic regression and log-
lenear models










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#1754 From: "somi_mckrish" <somi_mckrish@...>
Date:: Thu Sep 28, 2006 5:53 am
Subject:: Web Designing Projects
somi_mckrish
Offline Offline
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My Dear Friends.,


This is Somi McKrish From Vizag A.P. Looking for Web Designing
Projects on online. If any project proposal available from your side
please help me. I have a creative mind in designing websites, From 8
long years.

I work on Flash Professional and Adobe Photoshop CS2 Dream Weaver MX

Flash Professional for animations
Photoshop for Designing Layout for websites
Dream Weaver for Designing websites.

In my run I designed 10,000+ Templates in kinds

Somi McKrish.

#1753 From: "easwar_ps" <Moorthy.Easwara@...>
Date:: Thu Sep 28, 2006 3:45 am
Subject:: SAS Statistical Analysts reqd - Singapore XXX Bank, permanent positions
easwar_ps
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Hi Friends,

Note 1: I'M NOT A CONSULTANT, 'M AN EMPLOYEE OF THE BANK ITSELF...JUST
FORWARDING THIS INFO TO REFER ANY TALENTED GUY, AND GIVE HIM A BREAK
in HIS CAREER!THIS REQUIREMENT IS FOR MY TEAM.

We have immediate requirement for MANY Statistical Risk analysts!!!!
It's for XXXXX Bank, Singapore- permanent positions! Basic
responsibility is to build scorecards and BASEL models. SAS is a MUST
skill set required for the Role. Please forward this to all of your
friends, as opportunity doesn't knock twice. A short JD is given
below for better understanding about the role.

Note 2: We need Statistical Experience -Scorecard modelling/BASEL- a
Must, along with Banking as well as a mid-level SAS experience should
be good enough! And if you are not working in a bank currently,
please don't forward it..as non-banking resumes will get rejected!!

· Use data mining, data modelling and segmentation to build
scoring systems & Basel II credit risk models

· Ensure that analysis meets specifications of internal
modelling standards

· Use SAS to construct and clean datasets.

· Use SAS to perform standard statistical analysis,
modelling, profiling, and reporting.

· Use SAS to build predictive models - linear regression,
logistic regressions, etc.

· Validate existing credit risk models.

· Construct and Produce portfolio level MIS reports across
countries and products



Requirements


· Bachelors Degree in Statistics, Math, Operations Research
or other related filed (Masters a plus)

· 1-3+ years experience in data manipulation, analysis
and/or modelling

· SAS Certified Base Programmer a plus

· Proficient SAS programming skills and strong experience
with: DATA step data manipulation with arrays, do-loops, and merges;
SAS Macro language, SAS/GRAPH, PROC SQL experience.

Please mail me your resume TO EASWARA@..., in Word format.
Please forward it to your friends who are currently looking for a
change.

Cheerz
Moorthy

#1752 From: "Dr Nilen P Patel" <nilen_patel@...>
Date:: Wed Sep 27, 2006 9:04 am
Subject:: tips for effective presentation
nilen_patel
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few tips for effective powerpoint presentation
follow this link for slideshow
http://www.indvet.com/lit_web/TIPSPPT/index.htm
Regards
Nilen

#1751 From: "vrajak_msu" <vrajak_msu@...>
Date:: Wed Sep 27, 2006 5:11 am
Subject:: Difference B/W Logstic and Log-linear models
vrajak_msu
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dear friends
can any body give me a simple idea about Logstic regression and log-
lenear models

#1750 From: prakash pujar <prakash78pk@...>
Date:: Wed Sep 27, 2006 4:16 am
Subject:: Help needed!!!
prakash78pk
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Hello All,
 
This is prakash here (From Bangalore), i have around 1.5 years experiance in Marketing Research. i quited my job in last May 2006 (Because of my personal problems i went to my native now i came back to bangalore). Now i am looking for a Company they are working on Pure statistics (Analytics) and they use softwares like SAS and SPSS. Please inform me if you come to know that any openings which is suits my profile.
 
my contact number is 98805 39009 and
email id is prakash.pujar@...
 
Thank you very much for your help and support.
 
Best Regards,
 
Prakash
 
Nisha Muktewar <nisha_muktewar@...> wrote:
Hello All,
 
Can anyone tell me as to how the SQL SMALLINT & VARCHAR datatype is used in SAS? In my case I have the definition of a field in a file as SMALLINT & the content of the file is in EBCDIC format. I tried using S370FZD, S370FF, etc. But it doesnt seem to work.
 
Thanks a ton.
 
Nisha.

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Thanks and Regards,


Prakash K P.

Analyst

Bangalore


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#1749 From: Nisha Muktewar <nisha_muktewar@...>
Date:: Tue Sep 26, 2006 7:00 am
Subject:: SAS: Help needed!!!
nisha_muktewar
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Hello All,
 
Can anyone tell me as to how the SQL SMALLINT & VARCHAR datatype is used in SAS? In my case I have the definition of a field in a file as SMALLINT & the content of the file is in EBCDIC format. I tried using S370FZD, S370FF, etc. But it doesnt seem to work.
 
Thanks a ton.
 
Nisha.


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#1748 From: prashant rai <pk_stats@...>
Date:: Sun Sep 24, 2006 3:40 pm
Subject:: Query
pk_stats
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Dear All
 
Can any body let me know about the statistical tools commonly coming under umbrella of Bio-Statistics and related books.
Looking forward for positive responce
Prashant


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#1747 From: "stat700004" <stat700004@...>
Date:: Fri Sep 22, 2006 4:43 am
Subject:: Re: Multivariate Time Series
stat700004
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ya I agree Matlab has some in-built function for GARCH. But it is only
for Univariate GARCH, not multivariate. However some people already
wrote algo. for Multivariate GARCH, based on BEKK implementation,
flexM, etc, but I dont think they are much reliable. I will prefer R
for this type of analysis. R has "GARCH" function for Univariate case,
and "mgarchBEKK" for bivariate case. However general multivariate case
yet to be come.

#1746 From: "shredfun" <shredfun@...>
Date:: Thu Sep 21, 2006 7:54 pm
Subject:: Re: Reg: Non parametric tests
shredfun
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as a bit of knitpicking ..I don't think that the distribution of your
random variable is ever known..it is just assumed..

People use nonparametrics for a more robust and flexible solution to
cover a wide set of data sets.
for further discussion reference:
http://sunsite.univie.ac.at/textbooks/statistics/stnonpar.html

--- In Statisticians_group@..., karthik karthik
<g_s_karthik@y...> wrote:
>
> Hi
>   When we go for non parametric tests???
>
>   Case (1) The sample size is very small (<30)
>   Case(2) The distribution of the random variable is not known.
>
>   Is there anyother case???
>
>   Even in the second case, we can use central limit theorem and can
proeceed with parametric tests. (Then why non-parametric..?? Any
specific reasons??)
>
>   Thanks in advance.
>   Regards
>   Karthik.S
>
>
> ---------------------------------
> Yahoo! Messenger with Voice. Make PC-to-Phone Calls to the US (and
30+ countries) for 2¢/min or less.
>

#1745 From: karthik karthik <g_s_karthik@...>
Date:: Thu Sep 21, 2006 6:39 am
Subject:: Reg: Non parametric tests
g_s_karthik
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Hi
When we go for non parametric tests???
 
Case (1) The sample size is very small (<30)
Case(2) The distribution of the random variable is not known.
 
Is there anyother case???
 
Even in the second case, we can use central limit theorem and can proeceed with parametric tests. (Then why non-parametric..?? Any specific reasons??)
 
Thanks in advance.
Regards
Karthik.S


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#1744 From: swathi shetty <swathisona_shetty@...>
Date:: Thu Sep 21, 2006 4:42 am
Subject:: Re: Multivariate Time Series
swathisona_s...
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Hello

Matlab 6.5 version contains the functions for fitting the GARCH  model.
 
Swathi
maitytanmay <maitytanmay@...> wrote:
Hi friends,

Recently I am working on Multivariate Time series model like VARMA
(Vector autoregressive moving average) and also models like GARCH and
Multivariate GARCH.Would you give me some references of free
Statistical packages for calculation regarding this models?








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#1743 From: "umerafraz" <syed.umer@...>
Date:: Wed Sep 20, 2006 1:22 pm
Subject:: Re: To get out of loop in SAS
umerafraz
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Dear Madan



I would suggest you can use command "Leave"



For example



do until (l > h);

    m = floor ((l+h)*.5);

    if      k > a(m) then l = m+1;

    else if k < a then h = m-1;

    else do;

       put a(m)=;

       leave;

    end;

end;



Best Regards

Syed Umer A. Sharjeel.

Quality Representative



COMSIP AL A'ALI

      Cegel ec

P.O.Box 26949

Adliya

Kingdom Of Bahrain

Tel:  +973 17773006

Fax: +973 17770045

Mobile : +973 39301503

e-mail :   syed.umer@...

Website: http://www.comsip.com.bh


--- In Statisticians_group@..., "Madan Gopal Kundu"
<Madan.Kundu@r...> wrote:
>
>
> Dear all,
> We know that in C language we can use BREAK statement to get out
of a
> loop. What is the analogous statement in SAS that can meet my
purpose as
> BREAK dose in C language.
> Thanks in advance.
> Regards,
> MADAN
>
> (i) The information contained in this e-mail message is intended
only for the confidential use of the recipient(s) named above. This
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prohibited. If you have received this communication in error, please
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>
>
>  (ii) The sender confirms that Ranbaxy shall not be responsible if
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purposes, which are in violation of any existing laws and the same
shall solely be the responsibility of the sender and that Ranbaxy
shall at all times be indemnified of any civil and/ or criminal
liabilities or consequences there.
>

#1742 From: "Madan Gopal Kundu" <Madan.Kundu@...>
Date:: Wed Sep 20, 2006 6:48 am
Subject:: To get out of loop in SAS
madan4331
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Dear all,
We know that in C language we can use BREAK statement to get out of a
loop. What is the analogous statement in SAS that can meet my purpose as
BREAK dose in C language.
Thanks in advance.
Regards,
MADAN

(i) The information contained in this e-mail message is intended only for the
confidential use of the recipient(s) named above. This message is privileged and
confidential. If the reader of this message is not the intended recipient or an
agent responsible for delivering it to the intended recipient, you are hereby
notified that you have received this document in error and that any review,
dissemination, distribution, or copying of this message is strictly prohibited.
If you have received this communication in error, please notify us immediately
by e-mail, and delete the original message.


  (ii) The sender confirms that Ranbaxy shall not be responsible if this email
message is used for any indecent, unsolicited or illegal purposes, which are in
violation of any existing laws and the same shall solely be the responsibility
of the sender and that Ranbaxy shall at all times be indemnified of any civil
and/ or criminal liabilities or consequences there.

#1741 From: "stat700004" <stat700004@...>
Date:: Tue Sep 19, 2006 2:43 pm
Subject:: Re: Multivariate Time Series
stat700004
Offline Offline
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Use R

www.r-project.org

#1740 From: "Kjetil Halvorsen" <kjetilbrinchmannhalvorsen@...>
Date:: Tue Sep 19, 2006 5:14 pm
Subject:: Re: Multivariate Time Series
kjetil1001
Offline Offline
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Hola!

Something can be done in R (www.r-project.org) and then there is
jmulti (www.jmulti.de)

Kjetil Halvorsen

On 9/19/06, maitytanmay <maitytanmay@...> wrote:
Hi friends,

Recently I am working on Multivariate Time series model like VARMA
(Vector autoregressive moving average) and also models like GARCH and
Multivariate GARCH.Would you give me some references of free
Statistical packages for calculation regarding this models?








#1739 From: Patrick Burns <patrick@...>
Date:: Tue Sep 19, 2006 3:41 pm
Subject:: Re: Multivariate Time Series
burnsstat
Offline Offline
Send Email Send Email
 
I think investigating R (http://www.r-project.org)
would be a good idea.  I don't know if there are
implementations of multivariate GARCH, but there
is a working paper on the Burns Statistics website
detailing how to get a multivariate GARCH estimate
when only univariate GARCH estimators are available.

Patrick Burns
patrick@...
+44 (0)20 8525 0696
http://www.burns-stat.com


maitytanmay wrote:

> Hi friends,
>
> Recently I am working on Multivariate Time series model like VARMA
> (Vector autoregressive moving average) and also models like GARCH and
> Multivariate GARCH.Would you give me some references of free
> Statistical packages for calculation regarding this models?
>
>
>
>
>
>
>

#1738 From: "maitytanmay" <maitytanmay@...>
Date:: Tue Sep 19, 2006 1:00 pm
Subject:: Multivariate Time Series
maitytanmay
Offline Offline
Send Email Send Email
 
Hi friends,

Recently I am working on Multivariate Time series model like VARMA
(Vector autoregressive moving average) and also models like GARCH and
Multivariate GARCH.Would you give me some references of free
Statistical packages for calculation regarding this models?

#1737 From: Dr Nilen Patel <nilen_patel@...>
Date:: Tue Sep 19, 2006 4:32 am
Subject:: CV / Bio Data page on IndVet
nilen_patel
Offline Offline
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Dear friends
Just send your CV / Bio Data in word file to indvet@...
They will inform you by mail regarding your cv url.
It’s a great way to become online for recruiters…and for search engines.
Try it… It is really very easy
See the CV URL of mine on IndVet.
Regards,
Nilen
 


Dr. Nilen P. Patel
M.V.Sc. Pharmacology
AYURVET LIMITED
Village Katha, PO Baddi,
Tehsil Nalagarh,
Dist. Solan (HP) 173201
Phone: +91 9318834908


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#1736 From: "Vivek Rangachari" <vivrang@...>
Date:: Tue Sep 19, 2006 4:32 am
Subject:: Re: Confusion!!
vivranga
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Dear Madan,
 
Thanks a lot for clearing by doubt about probability and frequency distribution!! As far as the second question is concerned I am sorry for not making the question clear. Here is what I wanted.

I have a population of the weights of 1000 people. In order to determine the sample mean I go through the following process. I am confused as to which of the two processes is the correct one :

1) Population (1000)
2) Take some observed values (say, 10)
3) Find its mean
4) Repeat the process from step 2 till you get a sample of means (at least 30 such steps is to repeated from step 2 so that we get a normal distribution of the sample mean i.e keep taking 10 values from the population and find its mean; do it 30 or more times)


OR

1) Population (1000)
2) Take a sample of at least 30 or more (say, 45)
3) Find its mean
4) Repeat step 2 (I do not know how many times) till you get a normal distribution.

I wanted to clarify which is the right process and how many observed values and sample values is required.

Thanks for your help

Regards

Viv



 
On 9/18/06, Madan Gopal Kundu <Madan.Kundu@... > wrote:

Dear Viv,

 

I cannot understand your question clearly. So I am trying to answer your second query.

<< What is the fundamental difference between
probalility distruibutions and frequency distributions?>>

 

Probability distribution: Values of random variable with corresponding probabilities

Frequency distribution: Values of random variable with corresponding frequencies.

 

Example: Let X be a random variable. Also assume that x is a particular value of X and f(x) and p(x) be the frequency (of x) and probability (that X takes value x) respectively. That means,

p(X=x) =Probability ( X=x)

f(x)= Frequency of x

 

      x           f(x)        p(x)

--------------------------

0                    2            2/10=0.2

1                    1            1/10=0.1

2                    3            3/10=0.3

3                    0            0/10=0.0

4                    4            4/10=0.4

  -------      -------        --------

Total           10               1.0

 

Here {x, f(x)} will be known as frequency distribution of random variable X

Whereas {x, p(x) } will be known as probability distribution of random variable X

 

Hope it helps.

 

Regards,

MADAN

 

 


From: Statisticians_group@... [mailto:Statisticians_group@...] On Behalf Of vivranga
Sent: 18 September 2006 11:06
To: Statisticians_group@...
Subject: [Statisticians_group] Confusion!!

 

I am new to stats and have a couple basic questions regarding
sampling , the central limit theorem and probability.

If the sample size is 30 or greater then the sample means follow a
normal distribution.I wanted to know the minimum size of the
observations in each sample and its limits. Can I take 30 samples
each having 2 observations with the knowledge that the means of
these samples would follow a normal distribution?

Also I would like to get an intuition about probability
distributions. What is the fundamental difference between
probalility distruibutions and frequency distributions?

Can anyone please let me know about these as I am not able to
progress much without getting my basics clear :-)

Thanks

Viv







(i) The information contained in this e-mail message is intended only for the confidential use of the recipient(s) named above. This message is privileged and confidential. If the reader of this message is not the intended recipient or an agent responsible for delivering it to the intended recipient, you are hereby notified that you have received this document in error and that any review, dissemination, distribution, or copying of this message is strictly prohibited. If you have received this communication in error, please notify us immediately by e-mail, and delete the original message.


(ii) The sender confirms that Ranbaxy shall not be responsible if this email message is used for any indecent, unsolicited or illegal purposes, which are in violation of any existing laws and the same shall solely be the responsibility of the sender and that Ranbaxy shall at all times be indemnified of any civil and/ or criminal liabilities or consequences there.



--
"If investing is entertaining, if you're having fun, you're probably not making any money." - Soros

#1735 From: "bhgirish30" <bhgirish30@...>
Date:: Tue Sep 19, 2006 5:07 am
Subject:: Where to learn SAS in Delhi
bhgirish30
Offline Offline
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I would request you all to give me suggestion where to learn SAS
package in Delhi

#1734 From: Deepak Manohar <m_deepak_stat@...>
Date:: Mon Sep 18, 2006 11:20 am
Subject:: A help
m_deepak_stat
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Dear Learned Statisticians
I would like to know the fundamentals of Multi level modelling, its definition and application. Its quite urgent for a project so please do the need full to me
Thanking you
With regards
Deepak M
 


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#1733 From: "Madan Gopal Kundu" <Madan.Kundu@...>
Date:: Mon Sep 18, 2006 10:24 am
Subject:: RE: Confusion!!
madan4331
Offline Offline
Send Email Send Email
 

Dear Viv,

 

I cannot understand your question clearly. So I am trying to answer your second query.

<< What is the fundamental difference between
probalility distruibutions and frequency distributions?>>

 

Probability distribution: Values of random variable with corresponding probabilities

Frequency distribution: Values of random variable with corresponding frequencies.

 

Example: Let X be a random variable. Also assume that x is a particular value of X and f(x) and p(x) be the frequency (of x) and probability (that X takes value x) respectively. That means,

p(X=x) =Probability (X=x)

f(x)= Frequency of x

 

      x           f(x)        p(x)

--------------------------

0                    2            2/10=0.2

1                    1            1/10=0.1

2                    3            3/10=0.3

3                    0            0/10=0.0

4                    4            4/10=0.4

  -------      -------        --------

Total           10               1.0

 

Here {x, f(x)} will be known as frequency distribution of random variable X

Whereas {x, p(x)} will be known as probability distribution of random variable X

 

Hope it helps.

 

Regards,

MADAN

 

 


From: Statisticians_group@... [mailto:Statisticians_group@...] On Behalf Of vivranga
Sent: 18 September 2006 11:06
To: Statisticians_group@...
Subject: [Statisticians_group] Confusion!!

 

I am new to stats and have a couple basic questions regarding
sampling , the central limit theorem and probability.

If the sample size is 30 or greater then the sample means follow a
normal distribution.I wanted to know the minimum size of the
observations in each sample and its limits. Can I take 30 samples
each having 2 observations with the knowledge that the means of
these samples would follow a normal distribution?

Also I would like to get an intuition about probability
distributions. What is the fundamental difference between
probalility distruibutions and frequency distributions?

Can anyone please let me know about these as I am not able to
progress much without getting my basics clear :-)

Thanks

Viv







(i) The information contained in this e-mail message is intended only for the confidential use of the recipient(s) named above. This message is privileged and confidential. If the reader of this message is not the intended recipient or an agent responsible for delivering it to the intended recipient, you are hereby notified that you have received this document in error and that any review, dissemination, distribution, or copying of this message is strictly prohibited. If you have received this communication in error, please notify us immediately by e-mail, and delete the original message.


(ii) The sender confirms that Ranbaxy shall not be responsible if this email message is used for any indecent, unsolicited or illegal purposes, which are in violation of any existing laws and the same shall solely be the responsibility of the sender and that Ranbaxy shall at all times be indemnified of any civil and/ or criminal liabilities or consequences there.

#1732 From: "vivranga" <vivrang@...>
Date:: Mon Sep 18, 2006 5:36 am
Subject:: Confusion!!
vivranga
Offline Offline
Send Email Send Email
 
I am new to stats and have a couple basic questions regarding
sampling , the central limit theorem and probability.

If the sample size is 30 or greater then the sample means follow a
normal distribution.I wanted to know the minimum size of the
observations in each sample and its limits. Can I take 30 samples
each having 2 observations with the knowledge that the means of
these samples would follow a normal distribution?

Also I would like to get an intuition about probability
distributions. What is the fundamental difference between
probalility distruibutions and frequency distributions?

Can anyone please let me know about these as I am not able to
progress much without getting my basics clear :-)

Thanks

Viv

#1731 From: "Robert A. LaBudde" <ral@...>
Date:: Mon Sep 18, 2006 6:09 am
Subject:: Proper model for interlaboratory study
rlabudde
Offline Offline
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I have little experience with binary data or logistic regression.

I am interested in doing a simple analysis of an interlaboratory study of a
rapid presence-absence test kit vs. a reference method.

There are say 8 laboratories, each of whom analyze the same sample in
replicate (say 10 times). Each replicate corresponds to a pair of test
results (Test method +/- and reference method +/-). Obviously each
replicate is a matched pair, or repeated measure. There are a total of 8 x
10 x (2) = 160 data or 80 pairs, each of the form ++,+-,-+ or --.

Sensitivity is defined as the % of the time the two methods agree on a +
result, and specificity is defined as the % of the time the two methods
agree on a - result.

There would appear to be a number of questions arising from such a study:

Q1. Is there a significant difference between laboratories? I.e.,
heterogeneity.

Q2. Is there a significant difference between the two methods? (Based on
the difference of sensitivity of the two methods?)

Q3. What is the best point and interval estimates for the sensitivity and
specificity of the test method?

Q4. Is there a convenient manual method for answering the above questions?

Q5. What is the likelihood function for this experiment?

Q6. What logistic regression model should be used? What dependent variable
should be fit?

Q7. How would the logistic regression be implemented in SAS? (I.e., PROC
LOGISTIC lines.)

If anyone is willing to answer one or more of these questions, I would be
very grateful.

Thanks.
================================================================
Robert A. LaBudde, PhD, PAS, Dpl. ACAFS  e-mail: ral@...
Least Cost Formulations, Ltd.            URL: http://lcfltd.com/
824 Timberlake Drive                     Tel: 757-467-0954
Virginia Beach, VA 23464-3239            Fax: 757-467-2947

"Vere scire est per causas scire"
================================================================

#1730 From: Frank Isackson <fisackson@...>
Date:: Sat Sep 16, 2006 7:56 pm
Subject:: Re: fisher and lee , breckling
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Fisher, N.I, Lee, A.J. (1994). Time series analysis of circular data. J.R Statist. Soc. B, 56(2), 327-339
Breckling, J. (1989). The Analysis of Directional Time Series. Lecture Notes in Statistics Series

On Sep 15, 2006, at 1:04 PM, nivas wrote:

hellp
has anybody have idea about fisher & lee, breckling correlation coefficients? can any one suggest me books or papers if yes??
 
 
Thanks
Nivas


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#1729 From: nivas <nivas_07@...>
Date:: Fri Sep 15, 2006 8:04 pm
Subject:: fisher and lee , breckling
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hellp
has anybody have idea about fisher & lee, breckling correlation coefficients? can any one suggest me books or papers if yes??
 
 
Thanks
Nivas


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#1728 From: "e.mediasurvey" <e.mediasurvey@...>
Date:: Wed Sep 13, 2006 2:52 pm
Subject:: Please participate in an energy & environmental poll surve
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#1727 From: Robert A LaBudde <ral@...>
Date:: Tue Sep 12, 2006 1:45 pm
Subject:: Re: log regression
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At 04:41 AM 9/12/2006, you wrote:
>Hi all,
>
>Can any one tell me what is log regression? I know
>about logistic regression, log-linear regression etc,
>but I have no idea about log regression.

E(Y) =  a + b ln X

================================================================
Robert A. LaBudde, PhD, PAS, Dpl. ACAFS  e-mail: ral@...
Least Cost Formulations, Ltd.            URL: http://lcfltd.com/
824 Timberlake Drive                     Tel: 757-467-0954
Virginia Beach, VA 23464-3239            Fax: 757-467-2947

"Vere scire est per causas scire"
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#1726 From: "Madan Gopal Kundu" <Madan.Kundu@...>
Date:: Tue Sep 12, 2006 11:43 am
Subject:: Re: McNemar test in SAS
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Dear Robert,

Thanks a lot for your kind response. It is quiet informative for me.

Thanks and Regards,
MADAN

-----Original Message-----
From: Robert Newcombe [mailto:newcombe@...]
Sent: 11 September 2006 20:29
To: Madan Gopal Kundu
Subject: Re: [Statisticians_group] McNemar test in SAS

Dear Madan,

I'm not familiar with what SAS does here. But it's very easy to compute
a McNemar test manually, simply calculate (b-c)^2 / (b+c) where b and c
are the two doscordant cell counts, this has asymptotically a chi-square
dist. with 1 df. For your data, chi-sq = 88, with p << 0.001. Or you
could use an exact binomial p-value which is 2 ^ -88 one-sided, or
preferably 2 ^ -87 two-sided. All of these are of course astronomically
statistically significant (2 ^ -87 is approx 10 ^ -26).

Given the 'overkill' statistical significance, a confidence interval
may be of greater interest. If an odds ratio is of interest, for example
in  retrospective casr-control study, this is simply estimated as b/c
i.e. 0/88 or 0. Then use your preferred method to get a CI for the
binomial proportion b/(b+c), then get the corresponding CI for b/c. If
the confidence limits for b/(b+c) are L and U, the CLs for b/c are
L/(1-L) and U/(1-U). The first block of the attached Excel file (which
is freely available either from my website or the statisticians' group
website) calculates a CI for the single proportion using the Wilson
score method. For b/(b+c) = 0/88, the 95% CI is 0 to 0.0418.   So the
95% CI for the odds ratio b/c is from 0 to 0.0418/0.9582 i.e. 0 to
0.0437.

On the other hand, if the data come from a crossover or longitudinal
study, the difference of proportions is of greater interest. Let a, b, c
and d be the four cells, with a+b+c+d=n. For your data, a=256, b=0,
c=88, d=0, n=344. Then the difference is (a+b)/n - (a+c)/n = (b-c)/n
which is -88/256 = -0.2558. The 3rd block of the Excel spreadsheet
calculates a CI for this using a good method, this is -0.3044 to -0.2112
here.  I'm attaching a pdf of the paper that presents this method.

There is the usual correspondence (approximately at least) between CI
and p-value. Here, the p-value is extreme, the CI for the odds ratio is
well clear of the null hypothesis value of 1, and the CI for the paired
difference is well clear of the null hypothesis value of 0.

Hope this helps.


Robert G. Newcombe PhD CStat FFPH
Professor of Medical Statistics
Department of Epidemiology, Statistics and Public Health
Centre for Health Sciences Research
Cardiff University
4th floor, Neuadd Meirionnydd
Heath Park, Cardiff CF14 4YS
Tel: 029 2068 7247
Fax: 029 2068 7236

Home page
http://www.cardiff.ac.uk/medicine/epidemiology_statistics/research/stati
stics/newcombe
For location see
http://www.cardiff.ac.uk/locations/maps/heathpark/index.html


>>> "Madan Gopal Kundu" <Madan.Kundu@...> 11/09/06 05:39 >>>

I want to compute McNemar test with the following data:

data abc;
input x $ y $ count;
cards;
Absent Absent 256
Absent Present 0
Present Absent 88
Present Present 0
;
run;
proc freq data=abc;
table x*y/agree;
weight count;
run;

But log shows that:

NOTE: No statistics are computed for x * y since y has less than 2
nonmissing levels.

However, with the formula given in book it can be computed manually.
So
I am wonder why SAS does not produce the McNemar test statistic. Is
this
a software limitation???? ..... or anything else...



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