Blog Archives

T-tests

August 17, 2015
By
T-tests

One-Sample T-Tests To conduct a one-sample t-test in R, we use the syntax t.test(y, mu = 0) where x is the name of our variable of interest and mu is set equal to the mean specified by the null hypothesis. So, for example, if we wanted to test whether the volume of a shipment of

Read more »

Determine your Fitbit stride length using a GPS watch

July 15, 2014
By
Determine your Fitbit stride length using a GPS watch

I have been carrying my Fitbit One for a little over two years with me and it keeps tracking my daily steps. It also tracks my distance covered by multiplying those steps using the stride length which you can either provide explicitly or implicitly setting your heights. In the winter of 2012 I bought my … Continue reading...

Read more »

Analyzing Sleep with Sleep Cycle App and R

January 28, 2014
By
Analyzing Sleep with Sleep Cycle App and R

I have been tracking my sleep for almost two years now using my Fitbit. I started with the Fitbit Ultra and then moved on the the Fitbit One after it came out. In October 2013 I found out about the Sleep Cycle (Link) app for the iPhone. For weeks, Sleep Cycle was listed as the … Continue reading...

Read more »

Berlin Marathon 2014 Participants

November 12, 2013
By
Berlin Marathon 2014 Participants

After the 2013 Berlin Marathon sold out in less than four hours, the organizers decided to alter the registration process for 2014. First there was a pre-registration phase followed by a random selection from the pool of registrants to receive a spot. Those who were selected had to register until November 11th, 2013. Any spots … Continue reading...

Read more »

Five years of Weight Tracking

June 22, 2013
By
Five years of Weight Tracking

After I moved back from New Jersey in June 2008 I started to track my body weight more seriously. My routine usually consists of getting up and after finishing the morning bathroom I would step on my scale. That way I try to ensure that the condition for each weighing are as similar as possible. … Continue reading...

Read more »

Using R for Introductory Statistics, 3.1

May 21, 2010
By
Using R for Introductory Statistics, 3.1

Pairs of categorical data The grades data.frame holds two columns of letter grades, giving pairs of categorical data, like so: prev grade 1 B+ B+ 2 A- A- 3 B+ A- ... 122 B B This type...

Read more »

Using R for Introductory Statistics, Chapters 1 and 2

April 27, 2010
By
Using R for Introductory Statistics, Chapters 1 and 2

I'm working my way through Using R for Introductory Statistics, by John Verzani, a free version of which is available as SimpleR. Chapter 1 ...covers basics of R such as arithmetic, loading libraries and reading data. We also get an introduction to v...

Read more »

The R type system

February 21, 2010
By
The R type system

R is a weird beast. Through it's ancestor the S language, it claims a proud heritage reaching back to Bell Labs in the 1970's when S was created as an interactive wrapper around a set of statistical and numerical subroutines. As a programming language,...

Read more »

Pivot tables in R

January 9, 2010
By
Pivot tables in R

A common data-munging operation is to compute cross tabulations of measurements by categories. SQL Server and Excel have a nice feature called pivot tables for this purpose. Here we'll figure out how to do pivot operations in R.Let's imagine an experim...

Read more »

SQL group by in R

December 27, 2009
By
SQL group by in R

The R statistical computing environment is awesome, but weird. How to do database operations in R is a common source of questions. The other day I was looking for an equivalent to SQL group by for R data frames. You need this to compute summary statist...

Read more »

Sponsors

Mango solutions



RStudio homepage



Zero Inflated Models and Generalized Linear Mixed Models with R

Quantide: statistical consulting and training



http://www.eoda.de









ODSC

CRC R books series











Contact us if you wish to help support R-bloggers, and place your banner here.

Never miss an update!
Subscribe to R-bloggers to receive
e-mails with the latest R posts.
(You will not see this message again.)

Click here to close (This popup will not appear again)