Let us start with a logistic regression. Recall that a logistic regression divides 2 sets by a line (or a hyperplane if we have higher dimensions)
A logistic regression yields values from 0 to 1, and we can consider the process as making an evaluation. In the process we get data and we calculate our evaluation by a formula.
For example we may have the following assignment: to compute if we have enough goods in storage to last for a week of sales. This is quite a common problem, and say a clerk reports amounts of each item to a manager. The manager collects information, processes it and makes an evaluation: if every article quantity suffices.
Note that this is how a logistic regression functions.