cumulative probability
a running total of the chance of a score occurring at or below a certain point, where the largest running total is a value of 1.0. For example, a college teacher may want to know the cumulative probability values showing the chance that a grade selected from the entire set of grades on a recently given test would be an F, D, C, B, or A. If there were 8.3% Fs, 16.7% Ds, 33.3% Cs, 25% Bs, and 16.7% As, the cumulative probability values would be .083, .250, .583, .833, and 1.000, respectively, when totaling from the F to the A values.