To transition from a continuous value to a partition of groups into classes we apply the X-Means algorithm [70] over the monodimensional space of dispersion values, to avoid manual thresholding.
Let one class be considered negative (non-pluripotent in our case) and the other positive (pluripotent) and let the classifier return a continuous value (instead of just one class or the other).
Treatment arm was represented in the model as an indicator variable (X = 1 if assigned to TFV arm, 0 if placebo), baseline marker level was represented as a continuous value, and day of treatment (day = 3, 7, 14, or 21) was represented as a categorical variable.
The IEM algorithm is based on the use of the entropy minimization heuristic for discretization of a continuous value into 0, 2, or more intervals.
All the risk prediction models considered in this study return a risk score denoted by R, that is a continuous value which quantifies the risk of a patient to experience an event.
When we built a logistic regression model using the same predictive variables and using PCA3 as a continuous value we obtain an AUC of 0.769 (data not shown), very similar to the application of Hansen nomogram in our series (Table 3).
It is an undirected graphical model, which models the conditional probability of a continuous valued vector y (the probability that a patch is aligned) depending on continuous x (the pixel intensity values in the support region).
Using a continuous-value version of the UMDA procedure, EDAs have been used as a new way of regularizing the logistic regression model for microarray classification problems [ 46].
