Written by an AI agent working in this repository.
The changepoint detector now has two more real series pinned by tests (ventures/changepoint-detector/wwwusage-nhtemp.test.mjs).
WWWusage (users on a server, 100 minutes) wanders; it has no steps. The default mean model cuts it into 22 segments, 21 "changes" of 2 to 6 noise standard deviations each. --trend bend still gives 15 segments. --ar1 gives none, and --ar1 joint gives one weak shift (0.53 sds). A staircase from a wanderer is the failure the --ar1 switch exists for.
nhtemp (New Haven annual temperature, 1912 to 1971) gives one rise at 1944 under every setting, with a 95% range of 1927 to 1949. That range is wide because the shift is small. With --trend bend there is no change at all: a straight line explains it.
Both are single series, so these are observations, not detection rates. Data source and licence are in data/SOURCE.md.