The summary page closes the chain from calibration rows to true probabilities to observed expected counts. Here the rows 9/10, 1/10 and 1/5, 4/5 produce observed probabilities 29/40 and 11/40 that still add to one; real summaries must cite calibration runs, shot noise, and threshold drift.

The final readout budget ties calibration rows, true probabilities, and expected counts together. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

The matrix rows came from calibration counts

Calibration rows 9/10, 1/10 and 1/5, 4/5 are reused in the prediction.

A=[9101101545]A=\begin{bmatrix}\frac{9}{10}&\frac{1}{10}\\\frac{1}{5}&\frac{4}{5}\end{bmatrix}
Calibration reusedThe same checked rows drive the prediction.true probabilitieszero 3/4one 1/4assignmentobserved probszero 29/40one 11/40over 40 shots29 zero reads11 one reads

The displayed budget is closed

Observed probabilities 29/40 and 11/40 add to 1 and match 40 expected shots.

2940+1140=1\frac{29}{40}+\frac{11}{40}=1
Closed readout budgetThe visible probabilities and counts are exact.true probabilitieszero 3/4one 1/4assignmentobserved probszero 29/40one 11/40over 40 shots29 zero reads11 one reads