The probability for an outcome may show a logistic distribution (see above) relative to a final score. The parameters for the equation describing the distribution can be estimated based on reading the curve plotting the probability for each score.

probability =

= 1 / (1 + EXP((-1) * Y))

where

• The probability is 0.5 when Y = 0. Positive values for Y are associated with higher probabilities and negative values with smaller (opposite effects since multiply by -1).