Tricky, Tricky Credit Scoring System

1. In traditional CSS, it is not multivariate logistic regression, but multiple univariate logistic regressions.
We're running univariate logistic regression for each intervals.
If you visualize it, it looks like a 'line graph' with inflection points(?).

2. What logit in CSS is interested is not expected target value but the slope(=relationship with target =  how much score to give per unit increase in the variable).

3. Dummy variables are not used in a way they are used in typical machine learning problems. Don't get fooled.

4.