Displaying 20 results from an estimated 39 matches for "div898".
2006 Jul 30
2
NIST StRD linear regression
NIST maintains a repository of Statistical Reference Datasets at
http://www.itl.nist.gov/div898/strd/. I have been working through the
datasets to compare R's results to their references with the hope that
if all works well, this could become a validation package.
All the linear regression datasets give results with some degree of
accuracy except one. The NIST model includes 11 paramet...
2012 May 04
3
read-in, error???
Dear Users!
I encountered with some problem in data reading while I challenged R (and
me too) in a validation point of view.
In this issue, I tried to utilize some reference datasets (
http://www.itl.nist.gov/div898/strd/index.html).
And the result departed a bit from my expectations. This dataset dedicated
to challenge cancellation and accumulation errors (case SmLs07), that's why
this uncommon look of txt file.
Treatment Response
1 1000000000000.4
1 1000000000000.3...
2007 Jul 04
2
probabilty plot
Hi all,
I am a freshman of R,but I am interested in it! Those days,I am
learning pages on NIST,with url
http://www.itl.nist.gov/div898/handbook/eda/section3/probplot.htm,
I am meeting a problem about probability plot and I don't know how to
plot a data set with R.
Could somebody tell me the answer,and a example is the best! I will
look forward to your answer.
Thank you very much.
2012 Jun 25
2
Fractional Factorial - Wrong values using lm-function
...ve a question regarding the use of aov and
lm-functions. I'm doing a fractional factorial experiment at our production
site, and I need to familiarize myself with the analysis before I conduct
the experiment. I've been working my way through the examples provided at
http://www.itl.nist.gov/div898/handbook/pri/section4/pri472.htm
http://www.itl.nist.gov/div898/handbook/pri/section4/pri472.htm , but I
can't get the results provided in the trial model calculations. Why is this.
Here is how I have tried to do it:
> data.catapult=read.table("Fractional.txt",header=T) #Read the...
2005 Mar 23
2
R accuracy
Hello,
I am trying to test the precision of R on datasets from The Statistical Reference Datasets Project http://www.itl.nist.gov/div898/strd/index.html and I don't manage to understand how R is storing its results.
For example, I calculate a mean on the michelso dataset (100 values) and find:
> m=mean(michel)
> m
V1
299.8524
> print(m,digits=15)
V1
299.8524
> print(m,digits=22)
V...
2012 Feb 02
9
Modelo senoidal de datos temporales de radiación y prueba de Thom
...prueba
de Thom para verificar su homogeneidad [0].
De momento me encuentro con los siguientes problemas:
1- ¿Existe la prueba de Thom en R? ¿O debo crearme mi propia función?
2- Para la realización del modelo senoidal estoy siguiendo los pasos que
marcan en este texto:
http://www.itl.nist.gov/div898/handbook/eda/section4/eda4253.htm
pero me encuentro con los siguientes problemas:
1a - La serie que estoy utilizando tiene valores perdidos (ND) y hay
varias funciones, como spectrum o lag.plot, que no se pueden utilizar.
Yo los he reconvertido a 0, lo que no se si sera la correcto o me puede...
2004 Apr 02
3
Single Factor Anova
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
Hello all -
As I progress in R I am trying to automate functions I would have
normally farmed out to Excel, SPSS or Statistica. Single factor anova
is one of them. For example, a dataset from NIST StRD
(http://www.itl.nist.gov/div898/strd/anova/AtmWtAg.html) has two groups:
1 2
107.8681568 107.8681079
107.8681465 107.8681344
107.8681572 107.8681513
107.8681785 107.8681197
107.8681446 107.8681604
107.8681903 107.8681385
107.8681526 107.8681642
107.8681494 107.8681365
107.8681616 107.8681151
107.86...
2008 Apr 17
2
Design and analysis of mixture experiments
Hi,
I'm interested in experimental design and data analysis on mixtures, like
cake recipes where the sum of the components is fixed; e.g.
<http://www.itl.nist.gov/div898/handbook/pri/section5/pri54.htm>.
I can't believe that R doesn't have facilities to design and analyse such
experiments, but I haven't been able to find them (I have looked quite
hard!). Can anyone point me in the right direction?
Thanks in advance,
Keith Jewell
mailto:k.jewell a...
2007 May 31
3
Problem with Weighted Variance in Hmisc
The function wtd.var(x,w) in Hmisc calculates the weighted variance of x
where w are the weights. It appears to me that wtd.var(x,w) = var(x) if all
of the weights are equal, but this does not appear to be the case. Can
someone point out to me where I am going wrong here? Thanks.
Tom La Bone
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2003 Aug 15
2
help with Tukey Mean-Difference Plot
...t. However the correlation line is
parallel displaced depending on a clinical condition. I thought to a
Tukey Mean Difference Plot would show me the difference betweenthe
two values.
I don't have the literature how the plot gets constructed, but my understanding
from
http://www.itl.nist.gov/div898/software/dataplot/refman1/auxillar/meandiff.htm
is that the first from each distribution a qq plot is constructed and
than the coardiantes of the qq-plot are transformed according the
formula x=x+y/2 and y=x+y.
I tried this with
tmd(xyplot(a ~ b| c, data=data)) with
a and b holding my log10 t...
2005 Jan 13
2
chisq.test() as a goodness of fit test
...ow can I use chisq.test() as a goodness of fit test?
Reading man-page I?ve some doubts that kind of test is
available with this statement. Am I wrong?
X2=sum((O-E)^2)/E)
O=empirical frequencies
E=expected freq. calculated with the model (such as
normal distribution)
See:
http://www.itl.nist.gov/div898/handbook/eda/section3/eda35f.htm
for X2 used as a goodness of fit test.
Any help will be appreciated.
Thank a lot. Bye.
Vito
=====
Diventare costruttori di soluzioni
Became solutions' constructors
"The business of the statistician is to catalyze
the scientific learning process."...
2006 Mar 13
1
bihistogram plots
Does anyone have code to plot bihistograms in R?
See http://www.itl.nist.gov/div898/handbook/eda/section3/bihistog.htm
for a description of
a bihistogram.
--
Hal Varian voice: 510-643-4757
SIMS, 102 South Hall fax: 510-642-5814
University of California hal at sims.berkeley.edu
Berkeley, CA 94720-4600 http://www.sims.berkeley.edu/~hal
2002 May 01
1
"normal probability plot" with a percentile scale?
I'd like to generate some plots like you'd see on the old "normal
probability graph paper", like the first plot in:
<http://www.itl.nist.gov/div898/handbook/eda/section3/normprpl.htm>
except the horizontal scale would have 1%, 5%, 25%, 50%, 75%, 95%,
99%, or similar quantiles, with associated tick/grid lines. [still
hunting around for a good example...] something like these, but with
the probability along the horizontal axis:
<http:...
2005 Jan 11
3
Kolmogorov-Smirnof test for lognormal distribution with estimated parameters
Hello all,
Would somebody be kind enough to show me how to do a KS test in R for a
lognormal distribution with ESTIMATED parameters. The R function
ks.test()says "the parameters specified must be prespecified and not
estimated from the data" Is there a way to correct this when one uses
estimated data?
Regards,
Kwabena.
--------------------------------------------
Kwabena Adusei-Poku
2006 Jul 14
2
References verifying accuracy of R for basic statisticalcalculations and tests
...kages to a certain number
> of decimal places on some benchmark calculations.
I don't know of any references, but maybe you can somehow "verify the
accuracy of R" by running some analysis with the "NIST Statistical
Reference Datasets"; the URL is http://www.itl.nist.gov/div898/strd/
So maybe you can run the analyses mentioned there and say that R
(hopefully) returned the correct results.
Hope this helps,
Roland
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This mail has been sent through the MPI for Demographic Rese...{{dropped}}
2009 Dec 22
2
ACF normalization.
Hi,
Can anyone please provide the formula used to compute ACF(nlme). I believe the one that is used in R is of the type mentioned on the website. Please correct me if I am wrong. The normalization of the numerator (Ch) has been done by 'N' where as I would like to do it by 'N-k'. Is there anyway in the present implementation of ACF to normalize it by 'N-k', where
2007 Jul 27
1
R codes for g-and-h distribution
hi!
I would like to ask help how to generate numbers from g-and-h distribution. This distribution is like normal distribution but span more of the kurtosis and skewness plane. Has R any package on how to generate them?
Any help will be greatly appreciated. Thank you so much!
Form,
Filame Uyaco
---------------------------------
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2006 Mar 02
1
Doubly Non-Central F-Distribution
Dear Professor
I have read your questions in the website on Doubly non-central
F-distribution. I am looking for source code for evaluating this
function now. I have matlab code but it's only accurate up to the 4th
decimal point. Dataplot is more accurate, but it is not user friendly as
you only can evaluate one function at a time. So I would like to know do
you have found any R code for
2012 May 11
0
NLS sensitivity to start= values or poles in data range
...fairly new to R and am trying to expand my knowledge beyond using R for simple summary statistics and basic tests. To that end I am attempting to write an interactive R-script that will perform a general rational function fit to a given dataset based on the example given at http://www.itl.nist.gov/div898/handbook/pmd/section6/pmd64.htm.
The problem that I seem to have is that the fitted function is nearly identical to the NIST results when I use their initial values (these are representative values that are close to actual data, but not taken from the dataset) for generating the starting point for...
2004 Mar 16
3
Terminology and canonical statistical user literature
...half-knowledge that I have is often sufficient to see that
many otherwise nice sources of statistical knowledge are
dangerously incomplete when it comes to explaining the
preconditions required for applying a certain technique
(One example: The extensive NIST handbook at
http://www.itl.nist.gov/div898/handbook/
fails to mention that the Wilcoxon rank sum test assumes a
continuous distribution underlying the sample)
This is not to speak of how to correctly interpret the results.
My situation is this:
- I often have a hard time understanding the R documentation
due to lack of background.
- I a...