Probabilistic density functions (top row), cumulative density functions (middle row) and hazard functions (bottom row) for the rate-based learning (Weibull distribution), cumulative learning (gamma distribution), cumulative-and-rate-based learning (Weibull-gamma distribution), and alternative, logistic models.

<p>The accumulation and change-of-learning-rate parameters {<i>N</i>, <i>D</i>} are for {1, 3}, {5, 1}, {8, 0.5} in the Weibull, gamma, Weibull-gamma models, respectively. The slope and intercept of the logistic model are 1 and 5, respectively. All four models (distributions) have an identical mean of 5.