Displaying 20 results from an estimated 1000 matches similar to: "probabilty plot"
2012 Feb 02
9
Modelo senoidal de datos temporales de radiación y prueba de Thom
Hola a todos:
Estoy intentado realizar un modelo senoidal de unos datos de radiación
solar con el fin de afrontar el relleno de la serie y aplicar la 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
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
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
2005 Jan 13
2
chisq.test() as a goodness of fit test
Dear R-Users,
How 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
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
---------------------------------
[[alternative HTML version deleted]]
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
2004 Nov 17
1
R: log-normal distribution and shapiro test
Hi,
from what you're writing:
"The logaritmic transformation
"shapiro.test(log10(y))" says: W=0.9773, p-value=
2.512e-05." it seems the log-values are not
distributed normally and so original data are not
distributed like a log-normal: the p-value is
extremally small!
Other tests for normality are available in package:
nortest
compare the log-transformation of your ecdf
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 parameters,
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
2008 Oct 23
3
Interpretation of t.test results
I have run a t.test in R, and received these results:
Two Sample t-test
data: rsa and umple
t = 0.9819, df = 10, p-value = 0.3493
alternative hypothesis: true difference in means is not equal to 0
95 percent confidence interval:
-76.1541 196.1541
sample estimates:
mean of x mean of y
508.3333 448.3333
Can someone give me a detailed interpretation of the above results?
Specifically,
2012 Jun 25
2
Fractional Factorial - Wrong values using lm-function
Hello.
I'm a new user of R, and I have 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
2007 Apr 12
3
Putting 2 breaks on Y axis
R plotting experts:
I have a bivariate dataset composed of 300 (x,y) continuous datapoints.
297 of these points are located within the y range of [0,10], while 2
are located at 20 and one at 55. No coding errors, real outliers.
When plotting these data with a scatterplot, I obviously have a problem.
If I plot the full dataset with ylim = c(0,55), then I cannot see the
structure in the data in
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
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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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
2004 Apr 02
3
Single Factor Anova
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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
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
2003 Aug 15
2
help with Tukey Mean-Difference Plot
Dear R users,
I would appreciate for some advise how to generate a Tukey
Mean-Difference Plot with the tmd function part of the lattice
library. I have two test results (log transformed) which showing a
correlation on a scatterplot. 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
2004 Sep 23
6
detection of outliers
Hi,
this is both a statistical and a R question...
what would the best way / test to detect an outlier value among a series of 10 to 30 values ? for instance if we have the following dataset: 10,11,12,15,20,22,25,30,500 I d like to have a way to identify the last data as an outlier (only one direction). One way would be to calculate abs(mean - median) and if elevated (to what extent ?) delete the