Displaying 20 results from an estimated 8000 matches similar to: "Minimum-chi-square estimation"
2005 Jul 10
1
O/T -2 Log Lambda and Chi Square
Hi R People:
Sorry about the off topic question.  Does anyone know the reference
for "-2 Log Lambda  is approx dist. Chi square", please?
It may be Bartlett, but I'm not sure....
thanks in advance!
Sincerely,
Laura Holt
mailto: holtlaura at gmail.com
2008 Jul 25
1
Chi-square parameter estimation
Hi. I have made 100 experiments of an M/M/1 queue, and for each one I have calculated both, mean and variance of the queue size. Now, a professor has told me that variance is usually chi-squared distributed. Is there a way in R that I can find the parameter that best fits a chi-square to the variance data? I know there's fitdistr()m but this function doesn't handle chi-square. I believe
2013 Aug 26
1
Hex string following key path
Hi,
Can somebody explain what is the hex string following the path to the
RSA key used for authentication? For an example, see last line in the
debug snippet shown below.
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug2: key: /Users/blah/.ssh/id_rsa (0x6fef81c1d114)
How is that value generated? Is it something I can
2014 Dec 16
1
Estimating bitrate during a real-time voip call
Hi Dragos,
The issue is that not all packet loss maybe congestion related. Often,
reducing bitrate seems to have no impact on improving packet loss.
Thanks,
Manpreet.
On Tue, Dec 16, 2014 at 2:09 AM, Dragos Oancea <droancea at yahoo.com> wrote:
>
> Hi
>
> You can start a VOIP call with 50 kbps bitrate and reduce the bitrate if
> there is packet loss.  You know if
2008 Oct 25
2
how to plot chi-square distribution in the graph
if i want to plot the chi-square distribution with a different degree of
freedom how can i plot it in the graph?Sometimes i plot the histogram and
cut it in a lot of piece.It's distribution like a chi-square.So i want to
plot the chi-square with a different degree of freedom to compare it .
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2006 Jun 30
2
Query : Chi Square goodness of fit test
I want to calculate chi square test of goodness of fit to test,
Sample coming from Poisson distribution.
please copy this script in R & run the script
The R script is as follows
########################## start
#########################################
No_of_Frouds<-
c(4,1,6,9,9,10,2,4,8,2,3,0,1,2,3,1,3,4,5,4,4,4,9,5,4,3,11,8,12,3,10,0,7)
N <- length(No_of_Frouds)
# Estimation of
2010 Dec 29
1
Problem applying Chi-square in R and Cochran's Recommendations
Sir,
I have a problem here while applying chisquare test to the following Data (
below the subject of this mail) ...when I wanted to test the significance
using three different free statistical packages, here R, EpiInfo and
OpenEpi.
*Only OpenEpi accepts the test based on Cochran's Recommendations. *
R says " chi squared approximation may be incorrect."
Does it mean the same as
2010 Aug 17
2
plotting functions of chi square
Hi! This is going to be a real newbie question, but I can't figure it out. 
I'm trying to plot densities of various functions of chi-square. A simple
chi-square plot I can do with dchisq(). But e.g. chi.sq/degrees of freedom I
only know how to do using density(rchisq()/df). For example:
plot(1, type="n",  xlab="", ylab="", xlim=c(0,2), ylim=c(0,7))
for (i
2008 Nov 07
4
chi square table
Hi,
How do we get the value of a chi square as we usually look up on the
table on our text book?
i.e. Chi-square(0.01, df=8), the text book table gives 20.090
> dchisq(0.01, df=8)
[1] 1.036471e-08
> pchisq(0.01, df=8)
[1] 2.593772e-11
> qchisq(0.01, df=8)
[1] 1.646497
>
nono of them give me 20.090
Thanks,
cruz
2008 Mar 02
2
difference between lrm's "Model L.R." and anova's "Chi-Square"
I am running lrm() with a single factor. I then run anova() on the fitted
model to obtain a p-value associated with having that factor in the model.
I am noticing that the "Model L.R." in the lrm results is almost the same
as the "Chi-Square" in the anova results, but not quite; the latter value
is always slightly smaller.
anova() calculates the p-value based on
2007 Mar 29
3
Tail area of sum of Chi-square variables
Dear R experts, 
I was wondering if there are any R functions that give the tail area
of a sum of chisquare distributions of the type:
         a_1 X_1 + a_2 X_2
where a_1 and a_2 are constants and X_1 and X_2 are independent chi-square variables with different degrees of freedom.
Thanks,
Klaus
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2006 Sep 04
1
Question on Chi-square of null model in sem package
Dear all,
I met a problem while doing SEM by sem package. I got a negative
chi-square of null model. Because the theoretical value of chi-square
cannot be negative, I checked the source code of sem.R in sem package
and I found the Chi-square of null model was computed by the following
expression:
result$chisqNull <- (N - 1) * (sum(diag(S %*% diag(1/diag(S)))) +
log(prod(diag(S))))
I think
2007 Oct 06
2
plot the chi-square distribution for n=1 through 10, on one plot
Dear help list.
I would like to plot the chi-square distribution for n=1 through 10, on
one plot.
How do I go about doing that?
I know how to plot one chi-square (using curve() for example), but
plotting 10 on one plot, that is too difficult for me.
I greatly appreciate your help.
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2011 Apr 22
1
Create 2x2 table from summary data and run chi square test.
R 2.12
windows 7
I am summary data that I would like to make into a 2x2 table representing counts positive vs. negative counts:
28/289  20/276
My table should look something like the following:
          group1 group2
Positive    28     20
Negative   289     276
How can a (1) create the 2x2 table
          (2) run a chi square test on the table?
I have tried the following code, but I
2008 Nov 09
1
Help on performing multiple chi-square tests
Hi,
I am new to R and I need to perform multiple chi-square tests.  I 
manage to perform one at a time, but is there a specific command 
to do multiple tests?
For example, I have a table that looks like this:
Marker Treatment Genotype1 Genotype2 Genotype3
1        A         23        57        32
1        B         43        59        12
...
...
n        A         ##        ##        ##
n      
2005 Jul 10
2
Off topic -2 Ln Lambda and Chi square
Dear R :
Sorry for the off topic question, but does anyone know the reference for
the -2 Ln Lambda following a Chi Square distribution, please?
Possibly one of Bartlett's?
Thanks in advance!
Sincerely,
Laura Holt
mailto: lauraholt_983 at hotmail.com
2005 Sep 13
1
Fisher's exact test vs Chi-square
Timothy,
I believe you are mistaken. Fisher's exact test give the correct answer
even in the face of small expected values for the cell counts. Pearson's
Chi-square approximates Fisher's exact test and can give the wrong
answer when expected cell counts are low. Chi-square was developed
because it is computationally "simple". Fisher's exact test,
particularly with tables
2009 Jun 03
1
Validity of Pearson's Chi-Square for Large Tables
Is Pearson's Chi-Square test for contingency tables asymptotically unbiased
for large tables (large degrees of freedom) regardless of the expected
values in each cell?  The rule of thumb is that Pearson's Chi-square should
not be used when large numbers of cells have expected values < 5.  However,
I compared the results on 4x4 contingency tables for R's chisq.test using
chi-square
2008 Nov 26
2
Chi-Square Test Disagreement
I was asked by my boss to do an analysis on a large data set, and I am
trying to convince him to let me use R rather than SPSS. I think Sweave
could make my life much much easier. To get me a little closer to this
goal, I ran my analysis through R and SPSS and compared the resulting
values. In all but one case, they were the same. Given the matrix
    [,1] [,2]
[1,]  110  358
[2,]   71  312
[3,] 
2004 Mar 23
1
Does Chi Square test for R differ from S-Plus?
I tried to run a GLM model using S-Plus and R. The same model and data were 
applied to the both packages. I got different results of  P(>|Chi|) for Anova, 
between S-PLus and R. Other estimates values are the same. 
P(>|Chi|) for S-Plus:
0.99565 0.99682 0.04871 0.84597 1.00000 0.99999 1.00000 1.00000 1.00000 0.95834
P(>|Chi|) for R:
0.00000 0.00000 0.00000  0.00000 0.00000 0.00000