similar to: Help on prediction intervals

Hello, I have two random variables with their percentiles which correspond to their probability distribution function. My objective is to sum these two random variables. There exists any algorithm or procedure in R capable of converting the percentiles to a probability density function? is the fast Fourier transform function of R(fft) capable of doing the sum with a convolution? I'm just

Hi All, This is a question not directly related to R itself, it's about how to deal with missing data. I want to build wind roses i.e. circular histograms of wind directions and associated speeds to look for trends or changes in the wind patterns over several decades for some meteo stations. The database I have contains hourly records of wind direction and speed over the past 50

*Hello All,* I tried figuring out the problem, I was trying to use laplacedot to predict the long term, which however would not do a good job. Then, I tried to do a point by point prediction and building the model again, everytime. It shows me better results. I tried writing my kernel function (matern covariance function), and attached is the result of that. Red lines show the fit and blue lines

Hi all I have a question about correct usage of persp(). I have a simple neural net-based XOR example, as follows: library(nnet) xor.data <- data.frame(cbind(expand.grid(c(0,1),c(0,1)), c(0,1,1,0))) names(xor.data) <- c("x","y","o") xor.nn <- nnet(o ~ x + y, data=xor.data, linout=FALSE, size=1) # Create an (x.y) surface and predict over all points d <-

Dear list, I am new to R and am using it to develop and test my own neural network codes. I need some training datasets that have the prediction results that should (approximately) appear when the datasets are passed through a good neural network, in order to test whether my code is working according to standards or not. Currently I am using nnet() and predict() function in nnet package to

Hi all, We are facing a problem while introducing ourselves to Reshape package use. Melt seems to work fine, but cast fails when we use mean as fun.aggregate. As you see here, length and sum work fine, but mean throws this same error whatever dataset we use. > cast(aqm, month ~ variable, length) month ozone solar.r wind temp 1 5 26 27 31 31 2 6 9 30 30

Hi. I started with a file which was a sparse 982x923 matrix and where the last column was a variable to be predicted. I did principle component analysis on it and arrived at a new 982x923 matrix. Then I ran the code below to get a neural network using nnet and then wanted to get a confusion matrix or at least know how accurate the neural net was. I used the first 22 principle components only for

Hello, I?ve got a statistical problem that I hope you can help me with. It doesn?t have to do directly with R, so if there?s another forum which would suit better, please tell me! Now here?s the problem: I want to derive confidence intervals for a variable X, which is - given the descriptive statistics - obviously negatively skewed and leptokurtic (i.e. peaked). My aim is to make a statement

R-helpers, I am using the package "drc" to fit a 4 parameter logistic model. When I use the predict function to get prediction on a new dataset, I am not getting the requested confidence or prediction intervals. Any idea what is going on? Here is code to reproduce the problem: --- library(drc) # Fit model to existing dataset in package spinach.model <- drm(SLOPE~DOSE, data =

Hello, I use nnet to do prediction for a continuous variable. after that, I calculate correlation coefficient between predicted value and real observation. I run my code(see following) several time, but I get different correlation coefficient each time. Anyone know why? In addition, How to calculate prediction accuracy for prediction of continuous variable? Aimin thanks, > m.nn.omega

Dear members, I'm fitting linear model using "lm" which has numerous auto-regressive terms as well as other explanatory variables. In order to calculate prediction intervals, i've used a for-loop as the auto-regressive parameters need to be updated each time so that a new forecast and corresponding prediction interval can be calculated. I'm fitting a number of these models

Dear all I have a model that looks like this: m1 <- lmer(Difference ~ 1+ (1|Examiner) + (1|Item), data=englisho.data) I know it is not possible to estimate random effects but one can obtain BLUPs of the conditional modes with re1 <- ranef(m1, postVar=T) And then dotplot(re1) for the examiner and item levels gives me a nice prediction interval. But I would like to have the prediction

I have an lme model that I want to use for prediction. With lm objects it is possible to use "interval" and "level" options of predict.lm to obtain prediction intervals. This seems not to be applicable for predict.lme. Is there a way to get prediction intervals also for lme predictions? Regards, Kari --

I have switched from The Unscrambler to R for pls regression analysis and have been able to calculate scores, coefficients, RMSEP from a large number of PLS1 and PLS2 models. The ultimate goal is to use these models for predicting unknown samples, which again is straight-forward with the built-in predict() function. However, I?m struggling with prediction uncertainty (i.e. confidence intervals) on

How can I get prediction intervals from a mixed-effects model? Consider the following example: library(nlme) fm3 <- lme(distance ~ age*Sex, data = Orthodont, random = ~ 1) df3.1 <- with(Orthodont, data.frame(age=seq(5, 20, 5), Subject=rep(Subject[1], 4), Sex=rep(Sex[1], 4))) predict(fm3, df3.1, interval='prediction') # M01 M01

As I understand it,  predict.lm(l ,newdata=nd ,interval="confidence") yields confidence bands for the predicted mean of new observations and lm.predict(l ,newdata=nd ,interval="prediction") yields confidence bands for new observations themselves, given an lm object l.   However with regard to {mgcv} although  predict.gam (g ,se.fit=TRUE ,interval= "prediction")

Hi R-users, >From the last week I've been working fitting a linear mixed model with random intercept and fixed shape (model4) for a data set with 37 individuals measured over time, using lme package. Results are at the end of this message. The outcome is score and the covariate is age. My question is: is possible (and how) to estimate both 95% confidence and prediction intervals for the

For a given linear regression, I wish to find the 2-tailed t-dist probability that Y-hat <= newly observed values. I generate prediction intervals in predict() for plotting, but when I calculate my t-dist probabilities, they don't agree. I have researched the issues with variance of individual predictions and been advised to use the variance formula below (in the code). I presume my

Hi. I have to forecast a time series of a Internet network traffic bitrate. The data are in file http://www.forumaltavilla.it/joomla/datitesi/dati.datand the sampling time is every 0.05 seconds. Now, i want to use HoltWinters forecasting. This is my script. dt=1.58443823e-9 #0.05 seconds in years dati.ts=ts(scan("dati.dat"),start=0,deltat=dt) model=HoltWinters(dati.ts)

I am using R 2.3.0, Is there a way to get prediction intervals using predict.gls? Any ideas would be appreciated. thanks, Spencer On 11/2/06, Frank McCown <fmccown@cs.odu.edu> wrote: > > I was wondering if anyone knows who should be contacted to add to the R > user-contributed documentation at > > http://www.r-project.org/other-docs.html > > There doesn't