search for: confident

Displaying 20 results from an estimated 5360 matches for "confident".

2005 Dec 29
1
use of predict() with confidence/prediction bands
To my understanding, a confidence interval typically covers a single valued parameter. In contrast, a confidence band covers an entire line with a band. In regression, it is quite common to construct confidence and prediction bands. I have found that many people are connecting individual confidence/prediction interval values produced with predict(object,sd.fit=T,type="conf/pred") and
2013 Jan 14
1
Zlib maildir reindex bug?
Hi Running dovecot 2.1.7 (from debian repo). We have some old compressed maildir messages with the wrong S= size in the filename (our fault). If I delete index files, log in to the mailbox and try to FETCH the bad message, dovecot complains about the incorrect message size, attempts to fix the filename and disconnects the client. However, it changes the filesize to the size of the message on
2013 Jan 14
2
One sided confidence limits for the regression line
Hi all, I am trying to plot the one-sided confidence limits for the regression line. It seems it is ok to use predict function to compute the two sided confidence limits. Does any one know a easy way to compute the one sided confidence limits? Thank you very much in advance. Hannah [[alternative HTML version deleted]]
2002 Jan 04
1
[S] confidence ellipsoid for model parameters
John Fox wrote: >The confidence ellipse for a pair of coefficients is just (with an >adjustment for size) the perpendicular shadow of the joint ellipsoid, in >the same sense that the confidence intervals for individual coefficients >are shadows of the joint ellipsoid or ellipse. The usual confidence ellipse >for 2 of q coefficients uses qf(.95, 2, df.error) to scale the ellipse; if
2011 May 06
2
Confidence intervals and polynomial fits
...value of the linear coefficient are really not very different, but predicted values using the 2.5% value of the quadratic coefficient and the 97.5% value of the quadratic coefficient are enormously, wildly divergent -- far beyond the range of variability in the original data, in fact. I feel quite confident, in a seat-of-the-pants sense, that the actual 95% limits of that quartic coefficient are much, much narrower than what R is giving me. Looking at it another way: if I just exclude the quartic term from the glm() fit, I get a dramatically narrower confidence band, even though the fit to the data...
2002 Nov 15
5
confidence interval in "predict.lm"
I am studying statistics using R and a book "Understandable Statistics", by Brase and Brase. The book has two worked examples for calculating a confidence interval around a predicted value from a linear model. The answers to the two examples in the book differ from those I get from R. The regression line, the standard error, and the predicted value in R and the book all agree for the
2010 Jul 21
1
"lmomRFA" package: error bounds/confidence intervals
Dear List I?m using the ?lmomRFA? package to fit different distributions to my data sample. To calculate the error bounds I used: regsimq(?) and sitequantbounds(?) So my questions are: Are error bounds and confidence intervals the same thing? And: Does regsimq(? boundprob = c(0.05, 0.95)) calculate the 90 or the 95% confidence interval? If error bounds and confidence intervals are
2012 Nov 06
1
Confidence intervals for Sen slope in zyp-package
Hi, I have a question about the computation of confidence intervals in the zyp package, in particular using the functions zyp.sen and confint.zyp, or zyp.yuepilon. (1) I'm a bit confused about the confidence intervals given by zyp.sen and confint.zyp. When I request a certain confidence interval in the function, the R output seems to deliver another confidence interval, e.g. when I set
2012 Mar 03
2
contour for plotting confidence interval on scatter plot of bivariate normal distribution
Dear all, I created a bivariate normal distribution: set.seed(138813) n<-100 x<-rnorm(n); y<-rnorm(n) and plotted a scatterplot of it: plot(x,y) Now I'd like to add the 2D-standard deviation. I found a thread regarding plotting arbitrary confidence boundaries from Pascal H?nggi http://www.mail-archive.com/r-help at r-project.org/msg24013.html which cites the even older thread
2012 Jun 07
2
Basic question about confidence intervals
Hi, I am again asking a generic question and the general response for such questions is cold. I am a beginner but use and write simple R scripts. I am looking for some ideas to calculate the confidence intervals based on this excerpt from the paper. Moreover it would help if someone points to material to read about degrees of freedom and any related concepts. Thanks,
2012 May 16
2
confidence intervals for nls or nls2 model
Hi all I have fitted a model usinf nls function to these data: > x [1] 1 0 0 4 3 5 12 10 12 100 100 100 > y [1] 1.281055090 1.563609934 0.001570796 2.291579783 0.841891853 [6] 6.553951324 14.243274230 14.519899320 15.066473610 21.728809880 [11] 18.553054450 23.722637370 The model fitted is: modellogis<-nls(y~SSlogis(x,a,b,c)) It runs OK. Then I calculate
2003 Jun 14
3
Confidence intervals plot
Hi all!! I am trying to plot several confidence intervals in a unique plot. That is, for each x, I have a confidence interval for a parameter related to x and I would like to plot them in the same plot, in order to compare them. The plot would look like some parallel vertical lines, each one corresponding to a x value. Their extrem points would be the confidence interval limits. I do not know if
2009 Sep 08
1
Confident interval for nls predictions
Hello all, I'm trying to establish some confidence intervals on predictions I am making using >predict(nls(...)) and predict.nls (unfortunately) does not utilize the se.fit option. A little more background is that I am trying to match the output with older SAS routines to maintain consistency. Because predict.nls does not provide se's for individual predictions, I have been using a
2007 Oct 09
3
2 Sample Confidence Interval - Formatting Data?
Hello all, I have to run a 2 Sample Confidence Interval on some data; the command for such intervals is "confint(...)", but in the help documentation it says that you need a "fitted model object" in order to run this command. What does that mean? The data is very small, it's: x=c(8,12,10,14,2,0,0) y=c(-6,0,1,2,-3,-4,2) and I want to be able to run a Confidence
2012 Feb 07
2
3D confidence ellipsoid with ellipse projections onto 2D plane
I have a 3xN matrix of parameters obtained from N regressions where the 3 parameters are jointly statistically significant. I would like to reproduce a 3D confidence ellipsoid projecting 2D ellipses onto the XY plane as in Figure 5.2 in this
2006 Jan 04
4
Discrepency between confidence intervals from t.test and computed manually -- why?
I am sure there is something simple here I am missing, so please bear with me. It concerns the computation of the confidence interval for a population mean. The data are 125 measurements of Cs137 radation, a sample data set from Davis "Statistics and Data Analysis in Geology" 3rd ed. (CROATRAD.TXT) ------------------ method 1: using textbook definitions: mean \pm se_mean * t-value mu
2006 Aug 10
1
glmmPQL question!
Hello Folks- Is there a way to create confidence bands with 'glmmPQL' ??? I am performing a stroke study for Northwestern University in Chicago, Illinois. I am trying to decide a way to best plot the model which we created with the glmmPQL function in R. I would like to plot my actual averaged data points within 95 % confidence intervals from the model. Plotting the model is easy,
2005 Apr 06
5
bootstrap vs. resampleing
Hi, I understand bootstrap can be used to estimate 95% confidence interval for some statistics, e.g. variance, median, etc. I have someone suggesting that by resampling certain proportion of the total samples (e.g. 80%) without replacement, we can also get the estimate of confidence intervals. Here we have an example of 1000 obsevations, we would like to estimate 95% confidence intervals for odds
2004 Feb 20
1
Confidence intervals for logistic regression
Hi, I found myself trying to figure out the type of confidence interval used for the coefficients of the logistic regression fit by using glm(family=binomial)... I suspect it is Wald confidence interval but am not sure...Does anybody know? Also, if so, how can I ask for likelihood ratio and/or score-based confidence intervals? Yours, Michael ~~~~~~~~~~~~~~~~~~~~~ Michael Levine Assistant
2012 Nov 23
1
Student-t distributed random value generation within a confidence interval?
Dear R-users! I?m faced with following problem: Given is a sample where the sample size is 12, the sample mean is 30, and standard deviation is 4.1. Based on a Student-t distribution i?d like to simulate randomly 500 possible mean values within a two-tailed 95% confidence interval. Calculation of the lower and upper limit of the two-tailed confidence interval is the easy part. m <- 30 #sample