Displaying 20 results from an estimated 36 matches for "multimodality".
2003 Apr 10
1
how to estimate parameters of multimodal distribution
Dear all
Please, is there any function or package for dealing with multimodal distributions?
I try to fit multimodal distribution or more precisely to find out mixture of normal
distributions which can lead to my actual data.
I use optim to find (in that case) two parameters but what I want is to let the
function find out arbitrary number of normal distributions underlaying my actual
data
2008 Sep 09
3
Modality Test
Dear Readers:
I have two issues in nonparametric statistical analysis that i need
help:
First, does R have a package that can implement the multimodality test,
e.g., the Silverman test, DIP test, MAP test or Runt test. I have seen
an earlier thread (sometime in 2003) where someone was trying to write
a code for the Silverman test of multimodality. Is there any other
tests that can enable me to know how many modes are in a distribution?
Second, i wo...
2010 Aug 20
0
Assign statistically relevant groups following multimodal distribution of data
Dear R mailing list members,
?
I am trying to find a way to assign samples into groups depending on their mathematical distribution in a computational way (that is, looped many times). My input is by row, a series of 34 samples per row with n rows. The goal would be to compute the distribution of row n and assign for that row n the samples into bins that would match the distribution of the given
2002 Aug 05
2
No subject
Hello,
I downloaded R today because I was told it has very good bootstrapping
abilities. What I need to do is to program it (or use an existing program)
to bootstrapping test for multimodality using nonparametric kernel density
estimates as proposed by Efron and Tibshirani (1993). If anyone can get me
started, I will be immensely grateful.
Thanks.
Sangeeta
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2010 Dec 20
4
Time Series of Histograms
Dear List,
I have a set of distributions recorded at an equal interval of time and I would like to plot them as series of horizontal histograms (with the x-axis representing time, and y-axis representing the bins) since the distribution shifts from unimodal to multimodal in several occasions. What I would like to see is something close to a violinplot, but I do not want a kernel density
2011 Dec 06
2
How to automate the detection of break points for use in cut
Dear R-users,
I would like to know if there is a function (in base R or the extension
packages) that would automatically detect the break points in a vector x
for later use in the cut function. The idea is to determine the boundaries
of the n intervals (n>=1) delimiting clusters of data points which could be
considered "reasonably" close, given a numerical vector x with unknown
2003 Jul 11
1
unimodality test
Dear R users,
I am interested in uni- bi- multimodality tests, for analysing reaction
times data. I was lead to Hartigan's dip test (Ann. Statistics, 13, 1985,
pp. 70-84, Applied Statistics, 34, 1985, 320-325). Not being a programmer
I am unable to translate the Fortran code given in ref. 2 into a R
function. I'd be glad to learn that someone al...
2003 Apr 14
1
NA in logical vector = data frame row numbers scrambled
Dear all.
RE how to estimate parameters of multimodal distribution
Thank to prof.Ripley for pointing me to mclust package, although I am not sure I
can apply it to my problem.
I have another question.
I need to change some of my values in data frame to NA.
I use something like
df[df$v1 < 5, 5:10] <- NA
which is OK if there are no NA values in v1.
here are some foo attempts
>
2003 Aug 22
5
No interest in partial auth?
Hi,
I don't mean to be annoying, but it seems like there isn't any interest in
partial authentication. Is this true? It's not a future plan for OpenSSH
to have this feature?
I'd just like to know if I'm on my own or not.
Thanks
Erik.
2002 Mar 26
3
ks.test - continuous vs discrete
I frequently want to test for differences between animal size frequency
distributions. The obvious test (I think) to use is the Kolmogorov-Smirnov
two sample test (provided in R as the function ks.test in package ctest).
The KS test is for continuous variables and this obviously includes length,
weight etc. However, limitations in measuring (e.g length to the nearest
cm/mm, weight to the nearest
2003 Jul 17
0
Silverman modality test
Dear R users,
I've written the following functions to implement Silverman's modality
test ("Using kernel density estimates to investigate multimodality", J.R.
Stat. Soc. B, 43, (1981), 97-99.), and I tested them on the Chondrite data
set (Good & Gaskins, J. Amer. Stat. Ass., 75, (1980), 42-56). Values for
the critical window width seem OK, which is not the case for the
significance levels.
If someone could give me a hint about what is wr...
2007 Nov 19
0
Using density() and turnpoint to Identify maxima in data
Hi
I have a large dataset which follows a multimodal distribution. And I
would like to identify the maxima. As the data is obtained from a
stochastic simulation, not all maxima in the data are "real maxima of
the dirstribution" but rather small random fluctuations. Unfortunately,
it is not possible for me to run more simulations to smooth the obtained
distribution.
What I am doing
2008 Jul 01
1
Plotting Bi-Gamma Distribution
Hi all,
I've tried to plot a vector which has two peaks in the density.
This link shows the figure.
http://docs.google.com/View?docid=dcvdrfrh_1dk9r2rc7
The red line is normal curve and green line is gamma curve.
Notice that red line can correctly fit the histogram that has two peaks
(i.e. red curve also has two peaks).
But the gamma curve there only has one curve.
Is there a way I can
2012 Jul 04
1
How do you impute missing data using Latent Class Model (poLCA package)
My problem is I have data with both categorial and numerical data,
currently only the categorical number contains missing data, was wondering
do I make a new dataframe containing only the categorical columns?
How would you use Latent Class Model specifically poLCA to impute the
missing data?
http://www.sscnet.ucla.edu/polisci/faculty/lewis/pdf/poLCA-JSS-final.pdf
The reason why I chose not to
2012 Apr 06
2
Bayesian 95% Credible interval
Hi all,
I have the data from the posterior distribution for some parameter. I want
to find the 95% credible interval. I think "t.test(data)" is only for the
confidence interval. I did not fine function for the Bayesian credible
interval. Could some one suggest me?
Thanks
[[alternative HTML version deleted]]
2003 Apr 24
0
AW: AW: estimating number of clusters ("Null or more")
> > It would be nice not only for me.
>
> I agree totally.
If you belong to R-contributors group then thanks a lot
in advance!
> The problem is that you have to formalize what a cluster is,
> and this is not a well defined notion.
> It has different meanings in different applications.
you are right if one follows the idea of full formalization of
the notion it
2009 Aug 28
1
breaking multi-modal histograms down into combinations of unimodal distributions
Dear All,
Does anybody know if there is a functionality in R to break histograms
that show a clear bi-modal (or multi-modal) distribution into a series
of unimodal histograms that added up result in the original histogram?
I was thinking of using QQ-plots (for which tools are available in R),
and then observing the number of times the observed quantiles cross
the 1:1 line, but this only gives an
2010 Apr 27
1
NFS automount failure
I'm having a problem with automount (autofs) from a server running
CentOS 5.4 to clients (example is CentOS 5.4). Client pulls automount
maps from NIS. THIS particular server is also used for login so it is
NIS bound as well (other servers are NOT).
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NIS Server Side... (content shortened)
2006 Jun 04
5
chan_capi-cm-0.6 and incoming calls problem
I have a problem receving calls via the ISDN line, using the followin
components
Asterisk 1.0.9 with asterisk@home
chan_capi-cm-0.6
AVM Fritz card
datalink protocol = point to multimode
I can make calls out with no problems so the issue is only incoming calls.
When I make the call from an external line to the ISDN line connected to
asterisk, I get a busy signal after about 5 seconds. I have
2006 Apr 06
3
OT: HOWTO: Create a 90mbit bonded link 600 m etre s away with Cat 3 or telco wire [long]
>Or, you could use a Corinex Phone Line Bridge which runs 128Mbits up to
2000
>feet. They also have a co-ax version which is 200mbits and goes 4000
feet...
>About $300 for both ends.
too bad they don't say what the bandwidth is at max distance - anyone know?