search for: multivarite

Displaying 5 results from an estimated 5 matches for "multivarite".

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2008 Jun 26
2
constructing arbitrary (positive definite) covariance matrix
...iated. Examples ######## COV<-function (p = 3, sd = 1, r= 0.5){ cov <- diag(sd^2, ncol=p, nrow=p) for (i in 1:p) { for (j in 1:p) { if (i != j) { cov[i, j] <- r * sd*sd } } } cov } > library(MASS) > ### Simualte multivarite gaussin data (works OK) > Sigma<-COV(p = 3, sd = 2, r= 0.5) > mu<-1:3 > mvrnorm(5, mu=mu, Sigma=Sigma) [,1] [,2] [,3] [1,] 1.2979984 1.843248 4.460891 [2,] 2.1061054 1.457201 3.774833 [3,] 2.1578538 2.761939 4.589977 [4,] 0.8775056 4.240710 2.203712 [5,] 0.2698180 2...
2005 Jan 13
2
multivariate diagnostics
Hi, there. I have two questions about the diagnostics in multivarite statistics. 1. Is there any diagnostics tool to check if a multivariate sample is from multivariate normal distribution? If there is one, is there any function doing it in R? 2. Is there any function of testing if two multivariate distribution are same, i.e. the multivariate extension of Kolomogr...
2006 Nov 07
1
multivariate splines
Hi, I am looking for an R package that would calculate multivarite (mostly 2d and 3d, tensor) cubic interpolating splines, so that I could evaluate these splines (and their derivatives) at many points (unkown at the time of calculating the spline polynomials) repeatedly. To make things concrete, I have an array V with dim(V) = k and gridpoint vectors grid=list(...
2006 Nov 15
3
how to create this design matrix?
Hi all, I have a multiple-linear regression problem. There are 13 columns of data, the whole data matrix is: n x 13, where n is the number of samples. Now I want to regress EACH of the first 12 columns onto the 13th column, with 2-parameter linear model y_i = b0 + b1 * x_i, where i goes from 1 to n, and b0 is the intercept. How do I create a design matrix to do the 12-column regression
2011 Dec 08
2
Relationship between covariance and inverse covariance matrices
Hi, I've been trying to figure out a special set of covariance matrices that causes some symmetric zero elements in the inverse covariance matrix but am having trouble figuring out if that is possible. Say, for example, matrix a is a 4x4 covariance matrix with equal variance and zero covariance elements, i.e. [,1] [,2] [,3] [,4] [1,] 4 0 0 0 [2,] 0 4