Frequencies and a contingency table in pandas

The file data.csv contains the answers of 20 students: odbor (field of study), rocnik (year of study) and spokojnost (satisfaction with their studies on a scale from 1 to 5). The values of odbor are kept in Slovak: Informatika = Computer Science, Matematika = Mathematics, Fyzika = Physics. Two students did not fill in their satisfaction. The column separator is a semicolon.

1. Load the file into df.
2. Store the proportion of students in each field of study (numbers from 0 to 1) in podiely.
3. Store the cumulative percentage frequency of satisfaction, sorted from the value 1 upwards, in kumulativne.
4. Store the contingency table odbor × rocnik with proportions by rows in po_riadkoch.

The check compares the computed values. The first run downloads pandas, after which it stays in the browser's memory.