In teaching statistics to non statistics majors we face a problem of understanding of mathematical formalism. In applied statistics courses we usually use real life data related to the main subject matter of our students. Such data are interesting for students and motivate final interpretation of statistical results. For demonstration of statistical concepts, computer simulated data with known statistical properties can be used. The advantage of such data is that the results of analysis can be compared with known and pre-defined properties of data. Many important statistical concepts and procedures can be shown in an obvious way using computer simulations and dynamic graphics. Such simulations can sometimes be more convincing than proofs and are appreciated by students.