rrange is a small unix util that, given a probability and a number of trials, turns your probability into an expected range. For example, let's say you flip a coin 40 times and want to know if it's biased. We assume the probability is 50% and run rrange as follows:
> rrange 0.5 40 > Around 20 ~ [14, 26]
This means that if you flip a coin 40 times and get, say, 24 heads, that's still no cause for concern, since you are still within the 95% expected confidence interval.
rrange is a Racket script. At present time you need to have Racket installed to run it.
Make sure you have Racket install at
/usr/local/bin/racket. Alternatively, if you are using OSX, you can run
ln -s /Applications/Racket\ v6.1.1/bin/racket /usr/local/bin/racketto avoid moving the Racket bin.
chmod +x rrange && mv rrange ~/bin/.
~/bin/is in your
Don't use this for anything serious. It is probably buggy and is based on statistical assumptions which may or may not apply in your case.