search for: measurements

...uld be two columns to represent the door open/closed measurement. If there are multiple datapoints with a given door/date/color combination, then they should be averaged. I would also like to make two columns to represent the number of datapoints that were averaged in determining the open/closed measurements. Jeffrey

Hello, I have two series, one with stream stage measurements every 5 minutes, and the other with barometric pressure measurements every hour. I want to subtract each barometric pressure measurement from the 12 stage measurements closest in time to it (6 stage measurements on either side of the hour). I want to do something like the following, but I don'...

I have a new device that takes measurements anywhere from every second, to every 15 minutes (depending on changes). The matrix has a date, time and Y column (Y is the measurement). For three days it is 25,000 rows. How do I average the measurements by every 30 minutes so my matrix is 48 rows per day? I have been working on this and cannot fi...

Hello, I have some measurements that I am trying to fit a model to. I also have uncertainties for these measurements. Some of the measurements are not well detected, so I'd like to use a limit instead of the actual measurement. (I am always dealing with upper limits, i.e. left censored data.) I have successfully run survr...

R-helpers: I would like to measure the correlation coefficient between the repeated measures of a single variable that is measured over time and is unbalanced. As an example, consider the Orthodont dataset from package nlme, where the model is: fit <- lmer(distance ~ age + (1 | Subject), data=Orthodont) I would like to measure the correlation b/t the variable "distance" at

If this has already been answered, my apologies in advance I am relatively new to this aspect of [R]. it is a bit of a basic question. I have 4 columns of data (site, Date, measurement type, value) in a tab delimited text file. Site is a site where measurements were collected, Date is a date in DD/MM/YYYY format, measurement is a code for the type of measurement made, and value just the value observed. So each site has multiple dates on which it was sampled and each date has multiple measurement types (fortunately only one value per measurement type...

Dear R help gurus, I have the following problem and I would be delighted if you could help me. >From a large (1500) cohort of patients we have been taking some measurements (ECG measurements, but its not important). The measurements are ordinal in 4 grades (Grade I-IV, grade IV being the most severe form). Every patients has been measured several times (usually once per year). The follow-ups are different for each patient (ranging from days to several years), thus som...

...the N items measures do not appear normal and I have used tests other than the t-test (chi-square, etc.) Sometimes the N items are measured after each one of several exposures and I used pairwise.t.test(). I have a situation where N is limited and I cannot increase it, therefore I arranged for M measurements of the N items to be made before and after exposure to the condition. Thus I have N x M measurements before the condition and N x M measurements after the condition. I assumed that performing M measures instead of 1 measure I would be able to provide more statistical power, however I don't kn...

Hi all, I have a data frame with some measured values of some animals. Sometimes the measurement failed, resulting in a NA for a measurement and sometimes the animal died, resulting in NA for all measurements. I have several groups of animals. How do I find the size of each group with only alive animals? And how do I find the size of the groups for each measurement? An example: l1 <- list(factor=c(24,24,24), val1=c(2, 3, NA), val2=c(4, NA, NA)) df <- as.data.frame(l1) df$factor <- factor(df$f...

...value 1 B 26 1 A 12 2 B 45 2 A 30 3 B 32 3 A 27 4 B 34 4 A 6 Is there an easy means by which I can subtract the after (A) measurements from the before (B) measurement for each vial in this data frame so I am left with a data frame that contains the vial number and difference between A and B? I've played around with writing a function and applying it with ddply, but haven't stumbled on a technique that works, though I feel...

Dear R user, I have a question on using R to analyze data with repeated measurements. I have 2 species with several strains (12) per species, each of which has been measured twice with for a given trait. No particular covariance, just two measures. Now I want to analyze the data with an ANOVA (aov) considering these repeated measures to get the MSq and SSq for the species and...

R 2.6.0 Windows XP At the risk of raising the ire of the R gods . . . I am looking for a package that will allow me to perform a poisson, quasipoisson, or negative binomial regression with adjustment for repeated measures. I have looked at glm, it does not appear to allow repeated measures. Although I can't get any help for lme or lme4 I remember that those packages perform repeated measures

I am using lme to handle repeated measurements. So far i can follow the examples from the book from pinheiro and bates. Now i get the problem , that i have "nested" repeated measuremnts, and i cant find out how to do the grouping part of the lme formula. 1.The simple problem ist that i have different Samples , from which i make repea...

...red comparison of mean vectors? Given: Anova: repeated measures on both factors, 1st factor = two different treatments, 2nd factor = 4 time points, where you are measuring the blood pressure at each of the time points. Hotelling T^2: You look at the difference in the 4x1 vector of blood pressure measurements for the two different treatments, where the four rows in the vector are the four time points. I am mainly interested in the main effects of the two treatments. Can someone please explain if there would be a difference in the two methods or any advantage in using one over the other? Thanks, Sean

Hello, I have a loop with 1000 repetitions which includes OR computation of an exposure factor and outcome. I compute OR like this: t<-table(exposure,outcome) oddsratio(t)$measure["estimate"] This gives me the estimates for exposure=0 and exposure=1 but exposure=0 is the reference group and i need only the estimate for exposure=1. I specified a matrix OR with 3 columns (for OR

...e. So we filter the 2 solutions each 6 times and get 12 filterd solutions. each of this filtrate is measured 8 times, so we get 12 *8 96 conc. values. i get a data table of: solution nr.filter nr.measures conc. 1 or 2 1 till 6 1-till 8 96 values because the concentrations are "repeated measurements" as i was told by a statistician (i am not) it is not allowed to make a anova with the formula: conc~solution+nr.filter+nr.measures. my question is: how can i solve this in R? thanks Nicolaas Busscher -- Dr.Nicolaas Busscher Universit?t GH Kassel Nordbahnhofstrasse: 1a, D-37213 Witzenhaus...

Hello, I've got a matrix (mail end) with the colnames x, y, z. In this matrix are different measurements. x and y are risign coordinates. With the following line I got the median value of z for all "x" AND "y" witch are the same (not every measurment in my list hast the same number of "x" and "y" values. Sometimes lines are missing. >MEDIAN <- na.omit(...

Dear All I have one centos server equipped with WiFi . I want to measure data rate speed on this connection . Is there any utility on my centos that can measure data speed on one specific Ethernet connection when transferring large size files through WiFi connection? Thank you -------------- next part -------------- An HTML attachment was scrubbed... URL:

Hello Listserve, Here is another question to keep you on your toes. Please consider the following toy dataset: a <- read.table(textConnection("fred sam joe alex measure.1 10 4 10 1 measure.2 10 4 2 8 measure.3 3 1 8 3 measure.4 5 1 3 3 measure.5 8 6 8 3 measure.6 9 5 1 0 measure.7 4 6 10 1 measure.8 3 6 8 9 measure.9 8 6 7 7 measure.10 7 8 9 8"), header = TRUE) And also please

I would be grateful if members of the list could point me in the direction of any code (preferably in R) that will allow me to estimate 95th percentiles from a set of repeated measurements. For example, we are interested in a clinical measurement where we have 3 measures for 14 subjects and 2 measurements on 24 subjects and single measurement on 36 subjects. We want to combine these to form a Normal range by using something that takes account that some of the measures are repeats. So...