BAND_K is 1.28 because +-1.28 standard deviations is the 10-90% interval of
a normal: the band means the same thing it always did, it is just estimated
from all the replicates instead of from two order statistics. Measured over
the 91 tier-2 cells, the percentile band moves more under a jackknife (0.074
against 0.072 standard deviations) and is about 10% narrower than the
interval it estimates, because sample percentiles from twenty points are
biased inward. Its width also drifts with the replicate count – 2.06, 2.24,
2.32 at n = 8, 14, 20 – where this one holds at 2.49, 2.54, 2.56.
Details
BURDEN_MIN is the share of an outcome a cell must carry to be tested. A
claim about how a burden is distributed is not informative about bands that
carry almost none of it, and those bands carry the most replicate noise. At
5% the tested cells still hold 94% of episodes. The cost is real and is
recorded against the claims that use it: a defect confined to the oldest ages
would not be caught.