High Bucket Observed Fraction - Calibration Bins, Exactly

Count the high bucket observed fraction exactly.

highlighted = computed this step

Count the high bucket positives

Rows A, B, and C have label 1. Row D has label 0.

1 + 1 + 1 + 0 = 3

The high bucket has 4 rows.

\text{rows in high bucket}=4

The observed positive fraction is 3 over 4, the same fraction as the bucket score.

\text{observed high}={3\over4}