The average energy is a source-bound weighted sum. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

Average energy uses the weighted numerator

The checked numerator is eight joules.

Enum=8 JE_{\rm num}=8\ {\rm J}
Weighted energy numeratorThe numerator is recomputed from energies and weights.states=s0:0J,w=4|s1:2J,w=2|s2:4J,w=1zTotal=7probabilities=s0:4/7=4/7|s1:2/7=2/7|s2:1/7=1/7energyNumerator=8 JaverageEnergy=8/7 JweightOrigin=explicit integer weights

The average divides by the partition total

The average energy is eight sevenths of a joule.

E=87 J\langle E\rangle=\frac{8}{7}\ {\rm J}
Average energyThe average-energy label cannot drift.states=s0:0J,w=4|s1:2J,w=2|s2:4J,w=1zTotal=7probabilities=s0:4/7=4/7|s1:2/7=2/7|s2:1/7=1/7energyNumerator=8 JaverageEnergy=8/7 JweightOrigin=explicit integer weights