(a) Logistic regression for classifying if an Iris flower is Versicolor ($y=1$) or setosa ($y=0$) using a single input feature $x$ corresponding to sepal length. Labeled points have been (vertically) jittered to avoid overlapping too much. Vertical line is the decision boundary. Generated by logreg_iris_1d.ipynb . (b) Same as (a) but showing posterior distribution. Adapted from Figure 4.4 of \citep{Martin2018}. Generated by logreg_iris_bayes_1d_pymc3.ipynb .