StatCounter - StatCounter is a simple but powerful real-time web analytics service that helps you track, analyse and understand your visitors so you can make good decisions to become more successful online.
PS Power and Sample Size - Statistical
Histats - Start tracking your visitors in 1 minute!
IBM SPSS Statistics - IBM SPSS Statistics is software that provides detailed analysis of statistical data. The company behind the product practically needs no introduction, as it's been a staple of the technology industry for over 100 years.
AFSAnalytics - AFSAnalytics.
RStudio - RStudio™ is a new integrated development environment (IDE) for R.