Paired Average Keeps the Difference - Signals and Noise in Physics Measurements Step by Step

Two finite averages can be subtracted without claiming population statistics. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

Each channel gets its own average

Channel A average is 7 volts and channel B average is 3 volts.

\bar A=7\ \text{V},\quad \bar B=3\ \text{V}

The paired difference is finite subtraction

The measured difference is 7 minus 3, giving 4 volts.

7+(-3)=4\ \text{V}