I recently had a task to take a look at some assessment (audit) data. I was assuming, rather hoping for data with a normal distribution and thought it would be a quick case of Pearson correlation between two columns: "Duration" and "Score". Just conjecture at this point as I did not understand what the assessment process
184 search results for "anova"
R 2.15.2 now available
As promised, the source distribution for R 2.15.2 is now available for download from the master CRAN repository. (Binary distributions for Windows, MacOS and Linux will be available from the CRAN mirror network in the coming days.) This latest point-update — codenamed "Trick or Treat" — improves the performance of the R engine and adds a few minor but...
R for Ecologists: Permutation Analysis – t-tests
You’ve carefully designed your experiment, you’ve meticulously collected your data, and you have a hypothesis to test. Unfortunately, your data is typical of ecology data: small sample sizes, messy, and non-normal. Your ideal test, the t-test, won’t work because of the … Continue reading →
Recoding Variables in R: Pedagogic Considerations
I was creating a dataset this last week in which I had to partition the observed responses to show how the ANOVA model partitions the variability. I had the observed Y (in this case prices for 113 bottles of wine), … Continue reading →
Power and Sample Size Analysis: Z test
This article provide a brief background about power and sample size analysis. Then, power and sample size analysis is computed for the Z test. Continue reading →
Color Palettes in HCL Space
This is a quick follow-up to my previous post about Color Palettes in RGB Space. Achim Zeileis had commented that, perhaps, it would be more informative to evaluate the color palettes in HCL (polar LUV) space, as that spectrum more accurately describes how humans perceive color. Perhaps more clear trends would emerge in HCL space,
Product revenue prediction with R – part 2
After development of predictive model for transactional product revenue -(Product revenue prediction with R – part 1), we can further improvise the model prediction by modifications in the model. In this post, we will see what are the steps required for model improvement. With the help of a set of model summary parameters, the data
ANOVAs and MANOVAs
# Anova's are frequently used in experimental setting when treatments is a categorical value and there are one or more response variables. Rather than testing the statistical significance of each categorical value with respect to the re...
Parse pdf files with R (on a Mac)
Inspired by this blog post from theBioBucket, I created a script to parse all pdf files in a directory. Due to its reliance on the Terminal, it’s Mac specific, but modifications for other systems shouldn’t be too hard (as a start for Windows, see BioBucket’s script). First, you have to install the command line tool
R 2.15.2 scheduled for October 26
The next minor update to R — version 2.15.2 "Trick or Treat" — will be released on October 26, R-core member Peter Dalgaard announced today. You can find the planned updates in the current NEWS file (scroll down to the section 'CHANGES IN R VERSION 2.15.1 patched'; the changes at the top of the file are planned for the...
Zero Inflated Models and Generalized Linear Mixed Models with R.
Zuur, Saveliev, Ieno (2012).
