# PyQRS

# 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.

# 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.