similar to: Questions on weighted least squares

Hi all, I am running a bivariate regression with the following: p1=c(184,155,676,67,922,22,76,24,39) p2=c(1845,1483,2287,367,1693,488,435,1782,745) I1=c(1530,1505,2505,204,2285,269,1271,298,2023) I2=c(8238,6247,6150,2748,4361,5549,2657,3533,5415) R1=I1-p1 R2=I2-p2 x1=cbind(p1,R1) y1=cbind(p2,R2) fit1=lm(y1~-1+x1) summary(fit1) Response 2: Coefficients: Estimate Std. Error t value

Hi all, I'd like to fit a multivariate regression with the variance of the error term porportional to the predictors, like the WLS in the univariate case. y_1~x_1+x_2 y_2~x_1+x_2 var(y_1)=x_1*sigma_1^2 var(y_2)=x_2*sigma_2^2 cov(y_1,y_2)=sqrt(x_1*x_2)*sigma_12^2 How can I specify this in R? Is there a corresponding function to the univariate specification lm(y~x,weights=x)??

Hi all, I am going to sample two variables from two exponential distributions, but I want to specify a covariance structure between these two variables. Is there any way to do it in R? Or is there a "Multivariate Exponential" thing corresponding to the multivariate normal? Thanks in advance. Sincerely, Yanwei Zhang Department of Actuarial Research and Modeling Munich Re America Tel:

Hi all, Assume I have a random vector with four variables, i.e. A=(a,b,c,d). I am able to get the covariance matrix of vector A, but how can I get the covariance matrix of vector B=(a,c,b,d) by manipulating the corresponding covariance matrix of A? Thanks. Sincerely, Yanwei Zhang Department of Actuarial Research and Modeling Munich Re America Tel: 609-275-2176 Email:

Hi all, I have n independent variables A_1, A_2, A_3,......,A_n, and each with known variances var(A_1), var(A_2),..., but unknown mean. How can I get the approximation of the variance of the product of the variables using numerical computation, i.e. var(A_1*A_2*A_3*.....*A_n)? Thanks. Sincerely, Yanwei Zhang Department of Actuarial Research and Modeling Munich Re America Tel: 609-275-2176

Hi all, I have a 4 by 4 matrix, and I want to switch row 2 and row 3 first, then switch column 2 and column 3. Is there an easy way to do it? The following is a tedious way to get what I want. But I wonder if there is a way to simplify this. > a=matrix(rnorm(16),4,4) > a [,1] [,2] [,3] [,4] [1,] 0.33833811 -0.9422273 -0.06181611 -1.8346134 [2,] -0.68167996

Hi all, I got another VAR question here and really appreciate if somebody would help me out :) I have five time series, say A,B,C,D,E. My objective is to predict the series A using the rest, that is, B, C, D and E. A Vector Autoregression Model should work here. But first of all, I should select which series of B, C, D and E to be include in the VAR model, as well as the number of lags. I wonder

Hi all, Is there an easy way to do cumulative matrix multipliation in R? What's the syntex? Thanks. Sincerely, Yanwei Zhang Department of Actuarial Research and Modeling Munich Re America Tel: 609-275-2176 Email: yzhang@munichreamerica.com<mailto:yzhang@munichreamerica.com> [[alternative HTML version deleted]]

Dear list, I have the following matrix. How can I make the following plot? 1. The x-axis has index 1:7, and the first column is plotted against index 1, second against 2, and so on. 2. I want the points from the left upper conner including the antidiagonal to be plotted with col=2, and the rest with col=3 [,1] [,2] [,3] [,4] [,5] [,6] [,7] [1,] 0.589 0.857 0.923 0.944 0.954 0.963

I want to load many files in the R. The names of the files are "Sim1.txt", " Sim2.txt", "Sim3.txt", "Sim4.txt", "Sim5.txt" and so on. Can I read them at one time? What should I do? I can give the same names in R. Thanks. For example: > tst=paste("Sim",1:20,".txt",sep="") # the file names > tst [1]

Hi, Can anyone help to write a more elegant version of my code? I am sure this can be put into a loop but I am having trouble creating the objects b1,b2,b3,...,etc. b1 <- rigamma(50,1,1) theta1 <- rgamma(50,0.5,(1/b1)) sim1 <- rpois(50,theta1) b2 <- rigamma(50,1,1) theta2 <- rgamma(50,0.5,(1/b2)) sim2 <- rpois(50,theta2) b3 <- rigamma(50,1,1) theta3 <-

Hi, I am using the FracSim library to simulate a time series. However, the simulate function ignores my attempt to set the RNG seed I need for reproducible research. The published docs and google have not yielded an answer, so any help greatly received. Thanks, Selwyn ## Example code snippet library(FracSim) ## simulate some 1d fractal data set.seed(1234) sim1 = fracsim.1d(h=0.5,k=1000,n=5000)

Dear useRs, I want to simulate a time series (stationary; the distribution of values is skewed to the right; quite a few ARMA absolute standardized residuals above 2 - about 8% of them). Is this the right way to do it? #-------------------------------- load("rdtb") #the time series > summary(rdtb) Min. 1st Qu. Median Mean 3rd Qu. Max. -1.11800 -0.65010 -0.09091

2015-02-27 10:25 GMT-06:00 A J Stiles <asterisk_list at earthshod.co.uk>: > O.K. So what does your existing Dial() statement in extensions.conf look > like? > apology, put the gateway was sangoma but is a openvox , all my outgoing calls out for this context: [my-mobile-out] exten => _NXXXXXXX,n,Dial(SIP/1003/${EXTEN},55,rT) exten =>

On Friday 27 Feb 2015, ricky gutierrez wrote: > the problem is that my pbx all incoming calls using only the channel > gsm 1 , the idea is that an incoming call to channel 1 is passed to > channel 2 Ah. *Incoming* calls are not something that is within your control; they have already been routed onto a line by your telco. So you will need to speak to someone at your telco about doing

I don't understand what is happening! I have a (large) object sim1, an matrix list with dim c(101,101) where each element is an 3*3 matrix. I am subsetting that with a matrix coo, of dim c(100,2), of unique indices, but the resulting object has length 99, not 100 as expected. Code reproducing the problem follows: library(RandomFields) set.seed(123) sim0 <- GaussRF(x=seq(0, 100, by=1),

I've installed R-2.9.2 (64 bit), unixODBC-2.2.14-p2 (64 bit) and RODBC_1.2-5 (64 bit) on a 64 bit Redhat Linux server (Red Hat Enterprise Linux Server release 5.4 (Tikanga), x86_64) release 2.6.18-164.2.1.el5. I've tested the ODBC drive via isql and the test was success: [yzhang@ROracleTest ~]$ isql -v DRTST yzhang test +---------------------------------------+ | Connected!

Dear all, My double for loop as follows, but it is little efficient, I hope all friends can give me a "vectorized" program to replace my code. thanks x: is a matrix 202*263, that is 202 samples, and 263 independent variables num.compd<-nrow(x); # number of compounds diss.all<-0 for( i in 1:num.compd) for (j in 1:num.compd) if (i!=j) { S1<-sum(x[i,]*x[j,])

To whoever this may concern I am trying to write a repeat loop and can't make out from the documentation on the website how exactly to construct the repeat, break structure of the loop. Below is the function sim2.dat that I am trying to create, in which firstly I create n random uniform(0,1) numbers. From there I assign values to k, P and F. From then on for each random number u[j] of u, I

If the observations are normally distributed and the 2xk design is balanced, theory requires that the tests for interaction and row effects be independent. In my program, appended below, this would translate to cntT (approx)= cntR*cntI/N if all R routines were functioning correctly. They aren't. sim2=function(size,N,p){ cntR=0 cntC=0 cntI=0 cntT=0 cntP=0 for(i in 1:N){