In this simulation, 100 numbers are either sampled from a normal distribution or a uniform distribution. The frequencies in each of 10 "bins" is then displayed in the "observed" column. The expected frequencies based on both a normal distribution (on the left) or a uniform distribution (on the right) are shown just to the left of the observed frequencies. For each bin the value (E-O)²/E is computed where E is the expected frequency and O is the observed frequency. The sum of these quantities is the value of Chi Square shown at the bottom.