Grid B F1 Fraction - F1 Score, Exactly

Build the F-score fraction from grid B counts.

highlighted = computed this step

Double TP for grid B

For grid B, two times TP is 2 times 1 = 2.

2\cdot1=2

The denominator is 2 + 0 + 2 = 4.

2 + 0 + 2 = 4

Grid B gives 2 over 4, which reduces to 1 over 2.

F_{\text{one},B}={2\over4}={1\over2}