1288 search results for "excel"

Beware the Friedman test!

February 14, 2012
By
Beware the Friedman test!

In section 10.4.4 of Serious stats (Baguley, 2012) I discuss the rank transformation and suggest that it often makes sense to rank transform data prior to application of conventional ‘parametric’ least squares procedures such as t tests or one-way ANOVA. There are several advantages to this approach over the usual approach (which involves learning and applying a new test such as Mann-Whitney U,

Read more »

Machine Learning Examples in R

February 12, 2012
By
Machine Learning Examples in R

This is a post that has been a long time in the making. Following on from the excellent Stanford Machine Learning Course I have made examples of the main algorithms covered in R.We have Linear RegressionFollowed by Neural NetworksAnd Support ...

Read more »

Revisiting homicide rates

February 10, 2012
By
Revisiting homicide rates

A pint of R plotted an interesting dataset: intentional homicides in South America. I thought the graphs were pretty but I was unhappy about the way information was conveyed in the plots; relative risk should be very important but number … Continue reading →

Read more »

managing projects using RStudio

February 10, 2012
By
managing projects using RStudio

We're continually amazed with new developments within RStudio, the integrated developed environment for R that we highlighted previously (Among others, Andrew Gelman agrees with us about its value). The most recent addition addresses one of our earlie...

Read more »

Monitoring Progress Inside a Foreach Loop

February 9, 2012
By

The foreach package for R is excellent, and allows for code to easily be run in parallel. One problem with foreach is that it creates new RScript instances for each iteration of the loop, which prevents status messages from being logged to the console output. This is particularly frustrating during long-running tasks, when we are often unsure...

Read more »

Monitoring Progress Inside a Foreach Loop

February 9, 2012
By

The foreach package for R is excellent, and allows for code to easily be run in parallel. One problem with foreach is that it creates new RScript instances for each iteration of the loop, which prevents status messages from being logged to the console output. This is particularly frustrating during long-running tasks, when we are often unsure how much...

Read more »

Early-February flotsam

February 7, 2012
By
Early-February flotsam

Mike Croucher at Walking Randomly points out an interesting difference in operator precedence for several mathematical packages to evaluate a simple operation 2^3^4. It is pretty much a divide between Matlab and Excel (does the later qualify as mathematical software?) … Continue reading →

Read more »

Comparing correlations update

February 5, 2012
By

I have just published R code for calculating CIs for differences between correlations on the Serious stats book blog. This covers independent correlations (taken from chapter 6 of the book) and dependent correlations (new R code written as a suppl...

Read more »

Comparing correlations: independent and dependent (overlapping or non-overlapping)

February 5, 2012
By
Comparing correlations: independent and dependent (overlapping or non-overlapping)

In Chapter 6 (correlation and covariance) I consider how to construct a confidence interval (CI) for the difference between two independent correlations.  The standard approach uses the Fisher z transformation to deal with boundary effects (the squashing of the distribution and increasing asymmetry as r approaches -1 or 1). As zr is approximately normally distributed

Read more »

RStudio Server: accessing the RStudio R IDE through your browser

February 1, 2012
By

I like having all my important documents and scripts in one single place. This saves me from having to synchronize them between the different workplaces I have, and makes backupping much less of a pain. One way of achieving this… See more ›

Read more »