similar to: R exponential regression

There are a couple of points to keep in mind when doing a log-transform of an exponential model, such as -- y = a*exp(b*x) 1. The implicit statistical model is multiplicative in the error. The implied statistical model of the log transform is -- log(y) = log(a) + b*x + u which implies -- y = a*exp(b*x)*exp(u) A linear regression in the log

Hi all, I have imported a value 3:00 from Excel into R using read.csv. I want R to recognise it as 3:00am (time data). How do I do it? Thanks in advance, Chris -- View this message in context: http://n4.nabble.com/R-treating-time-tp1008608p1008608.html Sent from the R help mailing list archive at Nabble.com.

Hi all, I have a dataset similar to the following Name Date Value A 1/01/2000 4 A 2/01/2000 4 A 3/01/2000 5 A 4/01/2000 4 A 5/01/2000 1 B 6/01/2000 2 B 7/01/2000 1 B 8/01/2000 1 I would like R to remove duplicates based on column 1 and 3 only. In addition, I would like R to remove duplicates based on the underlying and overlying row only. For example, for A, I would like to remove row 2 only

Hi all, I have written a note near each of my graphs using mtext. mtext(text,side=1,line=4,cex=0.5,adj=0) Then I have exported the graphs as a PDF file. pdf(file=name,paper='a4',width=7.27,height=10.69) The mtext appears OK in R. But it looks like it is bolded in the PDF file. http://n4.nabble.com/file/n2016971/graph.png I am not sure if this is actually my monitor/computer's

How to add trendline (i.e. straight line passing through maximum points) in graph. I have worked on the data given below. Please tell me how to add trendline in the graph. The script is as follows =================================== start ==================================================== # The data is as follows data <- c( 0.01, 0.02, 0.04, 0.13, 0.17 , 0.19 , 0.21 , 0.27 , 0.27 ,

Hi I would like to display the trendline and the R-square value in a xy scatter in R. For example if I want to plot f vs g I add the trendline using the commands below >library(quantreg) >plot(f,g) >abline(rq(g~f)) however I don't know how to display the R2 in the graph. Thank you in advance. Kind regards Maria [[alternative HTML version deleted]]

Dear all, I am using abline(lm ...) to insert a linear trendline through a portion of my data (e.g. dataset[,36:45]). However, I am finding that whilst the trendline is correctly displayed and representative of the data portion I've chosen, the line continues to run beyond this data segment and continues until it intersects the vertical axes at each side of the plot. How do I display the

Hi everyone, I have written a script which exports my graphs as a PDF file using the function pdf(). For instance, I run the script and it exports a PDF called "version 1". Then, I have got a new dataset and want to run the script again. What it usually does is overwriting "version 1". But I want it to check if "version 1" already exists. If so, then I want the new

Dear all, I have data in the following format : X-axis Y-axis <0 10% 0-20 20% 20-40 30% 40-60 40% ......... and so on. I want to plot a bar graph of the above. Also I would want to add a trendline passing either through the center of each bar or through the top. Is it also possible to get the r-squared and p-values for

Hi, I am trying to fit a logarithmic trendline to a scatterplot of a species accumulation curve. I've tried abline, lines, curve and scatter.smooth but none of these work. Can anyone help please, Kyran

Hi everyone, I'm trying to determine the significance of a trendline. From my internet search months ago, I came across the following post. I modified tim and dat for simiplicity. tim <- 1:10 dat <- c(0.17, 1.09 ,0.11, 0.82, 0.23, 0.38 ,2.47 ,0.41 ,0.75, 1.44) fstat <- summary(lm(dat~tim))$fstatistic p.val <-

OK this is bound to be something silly as I'm completely new to R - having started using it yesterday. However I am already warming to its lack of 'proper' GUI... I like being able to rerun a command by editing one parameter easily... try and do that in a Excel Chart Wizzard! I eventually want to use it to analyse some chemotherapy response / survival data. That data will not be

Hi, Is there a way to plot trendline with quantmod package? There is addLines function in the package but I can't seem to figure out how to use it (not well documented): > args(addLines) function (x, h, v, on = 1, overlay = TRUE, col = "blue") NULL so arguments "h" and "v" add horizontal and vertical lines. How does argument "x" work? I would like

Dear R-users, I have a basic question about how to determine the antilog of a variable. Say I have some number, x, which is a factor of 2 such that x = 2^y. I want to figure out what y is, i.e. I am looking for the antilog base 2 of x. I have found log2 in the Reference Manual. But I am struggling how to get the antilog of that. Any help will be appreciated! > version platform

Hi everyone, I have been searching for answers for the following questions but I don't have much success. The following questions may actually be quite simple. Any help would be greatly appreciated. (1) I have written a script which requires user input. I am using the readline() command.However, everytime when I run the script, R does not wait for the user input and proceed to the next line.

I am hereby forwarding the data & method use to calculate the Kolmogorov-Smirnov goodness of fit test made manually by me in R launguage which deffers with the actual inbuilt formula as shown below. Further I have plot the graph in R. In that graph how to add trendline (i.e. straight line passing through maximum points in plot) to a Plot. R script is as follows please run this script to see

Hi all, I have got 27 graphs to export (not a lot...I know!). How can I fit all of them into a single file like PNG without adjusting the size of the graphs? What's in my mind is like pasting graphs into Word, in which I can just scroll down to view the graphs. Thanks for your attention. Much appreciated. Chris -- View this message in context:

hi! i want to change the "robustness weights" used by loess. these are described on page 316 of chambers and hastie's "statistical models in S" book as r_i = B(e_i,6m) where B is tukey's biweight function, e_i are the residulas, and m is the median average distance from 0 of the residuals. i want to change 6m to, say, 3m. is there a way to do this? i cant

Dear sir, I am fitting a glm with default identity link: model<-glm(timetoacceptsecs~maleage*maletub*relweight*malemobtrue*femmobtrue) the model is overdisperesed and plot model shows a low level of linearity of the residuals. The overdispersion and linearity of residulas on the normal Q-Q plot is corrected well by using:

Hi folks: I think I'm having problems with figuring this one out: test1 <- function() { n <- 2 for(i in 1:n) { cat(paste("i =", i, "\n")); flush.console() n <- 5 # version 1 #n <<- 5 # version 2 #assign("n", 5, envir = environment(test1)) # version 3 } } I need the for(.) loop to run (say) n=5 times within the