Aggregates Can Hide Failure

A mean can summarize accepted readings, but it can also hide instability if you ignore the original series.

Keep both:

raw series
accepted subset
aggregate
rejected evidence

The aggregate is derived evidence. It should never replace the source observations.

Checkpoint

Compute one aggregate from only the values allowed by your declared rule. Then show how the conclusion changes if the rejected value is silently included or deleted.

Write one sentence explaining why the aggregate cannot prove sensor health by itself.