search for: multimodal

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 underlay...

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...

...ause I am considering only one row at a time, I don't?think I can really use the clustering tools available, as they take as input a matrix and cluster rows together. I have tried to make use of the Shapiro.test() function in order to rank my rows by pvalue using the normality test, hoping that multimodal distributions would stand out, without any success. I have also tried to use the hist() function with the output $counts. I was thinking?of looping on those to identify?if more than one maximum exists and then splitting the?data around those maxima. Would that be a ("brute-force") solutio...

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 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwie...

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 estimate... Any suggestions or advice will be great! Thanks in Advance, Enrico

...ically 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 content and unknown multimodal distribution. For instance, given for the vector x defined by set.seed(1234); x <- sort(c(rnorm(20,-1,0.1),rnorm( 10,5,0.1),rnorm(10,100,0.1))), this function would return a vector of 4 points: min(x), one value between 20 and 5, one value between 5 and 100, and max(x). Thank you in advance fo...

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...

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 val...

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.

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

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...

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 smoo...

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

...mal Distribution which may not hold for certain types of categorical and binary data. Yucel Recai, Yulei He, and Alan Zaslavsky point out in their May 2008 article in The American Statistician, naive rounding MI imputations can bias estimates, particularly when the underlying data are asymmetric or multimodal." However instead of using Yucel Recai, Yulei He, and Alan Zaslavsky's rounding strategy [ http://amstat.tandfonline.com/doi/pdf/10.1198/000313008X300912] , I opted for the Latent Class Model: http://spitswww.uvt.nl/~vermunt/ginkel2007.pdf Who are the authors of the R package poLCA. Tha...

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]]

...e. Like with those p-values. > Normal mixtures (sometimes with lots of components) are reasonable > approximations to a wide class of distributions, so the > validity of the approach is rather a question of your > cluster concept than of the distribution of the data. I do agree that multimodal normal mixture is a very powerful approximation basis for a wider class of distributions. But in context of data homogeneity criterion it is rather a weak basis. Indeed, simple lognormal distribution will be adequately approximated with more then one mode only. That pushes us automatically to a...

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

...:794 for /mdkm1/10 (/mdkm1/10) I've restarted the Server NFS services, Client autofs services AND the systems as a whole multiple times to no avail. Any ideas? Thanks, Trevor Cooper -- Trevor Cooper, M.Sc. Data Systems Programmer / System Administrator University of California, San Diego Multimodal Imaging Laboratory 8950 Villa La Jolla Dr., Suite C101 La Jolla, CA 92037 Phone: (858) 534-8259 Fax: (858) 534-1078

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

>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?