similar to: Clinical Trial data sets in public domain?

Hi Robert, People want different levels of automation in the software they use. What concerns many of us is the desire for the function "figure-out-what-this-data-is-import-it-and-get-rid-of-bad-values". Such users typically want something that justifies its use by being written by someone who seems to know what they're doing and lots of other people use it. One advantage of many R

I don't think my view is of interest to many, so offlist. I reject this: " I would consider data analysis work to be three stages: data preparation, statistical analysis, and producing the report." For example, there is no such thing as "outliers" -- data to be removed as part of cleaning/preparation -- without a statistical model to be an "outlier" **from**,

Hi again, Typo in the last email. Should read "about 40 standard deviations". Jim On Thu, Nov 30, 2017 at 10:54 AM, Jim Lemon <drjimlemon at gmail.com> wrote: > Hi Robert, > People want different levels of automation in the software they use. > What concerns many of us is the desire for the function >

Hi, I have a series of id's with multiple visits and questionnaire scores. This is a clinical trial that will be analyzed using the last observation carried forward method. In other words, in order to comply with intent to treat analysis when many subjects withdraw, data points for the last visit must be generated and filled in with the last observation. The ultimate goal is to tabulate the

R has a very wide audience, clinical research, astronomy, psychology, and so on and so on. I would consider data analysis work to be three stages: data preparation, statistical analysis, and producing the report. This regards the process of getting the data ready for analysis and reporting, sometimes called "data cleaning" or "data munging" or "data wrangling". So as

Hi Everyone, I have data in a long format e.g. there is one row per patient but each follow-up appointment is included in the row. So, a snippet of the data looks like this: TrialNo Drug Sex Rand Adate1 Date1 Dose1 Time1 Adate2 Date2 Dose2 Time2 B1001029 LTG M 15719 30/04/2003 15825 150 106 29/08/2003 15946 200 227 B1117003 LTG M 15734 30/04/2003 15825 200 91 03/09/2003 15951 250 217

A graph != A table. I'm talking about a page full of summary statistics and advanced statistics, with lots of cross categories on the top and left margin of the table, as opposed to a visual display with x-axis and y-axis, which is totally different. (An example of how this is done in another language is available at http://fivetimesfaster.blogspot.com ) For an AE table, you have an N and %

As noted on the R-project web site itself ( www.r-project.org -> Manuals -> R Data Import/Export ), it can be cumbersome to prepare messy and dirty data for analysis with the R tool itself. I've also seen at least one S programming book (one of the yellow Springer ones) that says, more briefly, the same thing. The R Data Import/Export page recommends examples using SAS, Perl, Python, and

Dear all, There have been a variety of discussions on the R list regarding the use of R in clinical trials. The following post from the STATA list provides an interesting opinion regarding why SAS remains so popular in this arena: http://www.stata.com/statalist/archive/2008-01/msg00098.html Regards, -Cody Hamilton

All, Is there an efficient way to apply say "mean" or "median" to a dataframe according to say all combinations of two variables in the dataframe? Below is a simple example and the outline of a "manual" solution that will work but is not very efficient (could also generalize this to a function). Searched the archives and docs but didn't see anything close to

Will R have more glitches on one operating system as opposed to another, or is it pretty much the same? robert

I hope that Marc doesn't mind, but I felt that part of his recent post was important enough to deserve it's own subject line rather then being lost in a 60-msg-long thread... On Sun, Jan 11, 2009 at 10:08 AM, Marc Schwartz <marc_schwartz at comcast.net> wrote: ... I strongly believe that the comments regarding R and the FDA are overly negative and pessimistic. The hurdles to

1) What is easy for one person may be very hard for another, so your question is really unanswerable. You do need to know C and Fortran to get through the source code. Get started soon reading the R Internals document if it sounds interesting to you... you are bound to learn something even if you don't stick with it. If you have questions about the internals though, you should read the Posting

All, The code below is for a pseudo dataset of repeated measures on patients where there is also a treatment factor called "drug". Time is treated as categorical. What code is necessary to test for a treatment effect at a single time point, e.g., time = 3? Does the answer matter if the design is a crossover design, i.e, each patient received drug and placebo? Finally, what would

Hi all, thank you for your patience. I am dealing with a large dataset detailing patients and medications Medications are hard to code, as they are (usually) meaningless unless matched with doses. I have a dataframe with vectors (Drug1, Drug2..... Drug 16) and individual patients are represented by rows. The vectors are actually factors, with 100s of possible levels (all the drugs the patient

Dear R-Helpers, Apologies in advance as this is partly (widely ?) OT. Not sure where to ask, R is my favorite computer tool (no kidding) and there are plenty of knowledgable and helpful people on the list. Background: There are discussions among experts and regulatory authorities (cf guideline http://www.emea.europa.eu/pdfs/human/ewp/056598en.pdf) that, in for example Amyotrophic Lateral

All, How does one extract the level-1 variance from a model fit via lmer()? In the code below the level-2 variance component may be obtained via subscripting, but what about the level-1 variance, viz., the 3.215072 term? (actually this term squared) Didn't see anything in the archives on this. Cheers, David > fm <- lmer( dv ~ time.num*drug + (1 | Patient.new), data=dat.new )

Great question. What do I want? I want my co-workers to stop using Excel spreadsheets for data entry, storage, and sharing! I want them to understand the value of data discipline. But alas . . . . I work in a county health department in the US. Between dplyr, stringr, grep, grepl, and the base R read() functions, I'm doing OK. I need to learn more about APIs, so I can see if I can make R

Hi David: In looking at your original post it is a bit difficult to ascertain exactly what your null hypothesis was. That is, you want to assess whether there is a treatment effect at time 3, but compared to what. I think your second post clears this up. You should refer to pages 224- 225 of Pinhiero and Bates for your answer. This shows how to specify contrasts. > -----Original Message-----

Hello-- I have a data for small population who took 1 drug at 3 different doses. I have the actual drug concentrations as well as predicted concentrations by my model. This is what I'm looking for: - Time vs Concentration by ID (individual plots), with each subject occupying 1 plot -- there is to be 9 plots per page (3x3) - Observed drug concentration is made up of points, and predicted drug