PyQRS

(Probabilities, Quantiles and Random Samples)

For any given probability distribution, PyQRS lets you:

calculate probabilities,
calculate quantiles (inverse probabilities),
draw random samples,
calculate a missing (non-integer) parameter value.

PyQRS was developed as a tool for students studying statistics. It is meant to replace traditional probability tables and at the same time it should enhance the students’ understanding of probability concepts. Therefore a graphical user interface was designed which shows all values in their natural position with respect to the probability (density/mass) function and with respect to the cumulative distribution function.

The PyQRS website has been moved to http://pyqrs.gitlab.io/PyQRS.

webapp

Experimental: A web application with similar functionalities as PyQRS runs from:
knypstat.shinyapps.io/pqrs
Preferably you should use it on a computer; a phone's screen is too small.

PCalc

Our first program (1993) replacing tables of probability distributions, was running on the command line under MS-DOS. It was written in Pascal by Sytse Knypstra and Arjen Merckens. In fact it was a combination of a calculator and a replacement of probability tables. Its interface language was Dutch.

Installation

Download the compressed file PCalc.zip (50 kB), unzip it and start PCalc.exe under the program DOSBox.

PQRS

Around the year 2000 PQRS (Probabilities, Quantiles and Random Samples) was designed as a successor to PCalc with a graphical user interface. PQRS was written in Delphi and runs under Windows. You can download the compressed file PQRS.zip (0.7 MB), unzip and run PQRS.exe.

PyQRS

In 2013 PQRS was rewritten in Python. In order to distinguish it from the previous PQRS version, and as a tribute to Python and its author, Guido van Rossem, the first letter in its name was replaced by 'Py'.

The PyQRS website has been moved to http://pyqrs.gitlab.io/PyQRS.