The 95% bootstrap interval included zero for the Spearman–Brown forecast error in posterior 8–13 Hz CE EEG agreement from 20 to 60 seconds across V0 and V1 in 39 ds007176 adults

We tested a recording time forecast for posterior 8–13 Hz log power across V0 and V1 in 39 adults. The source was OpenNeuro ds007176 version 1.0.1. We treated CE as closed eyes. The same people supplied the 20-second and 60-second scores. Agreement ICC(A,1) was 0.770 at 20 seconds. The Spearman–Brown formula forecast 0.910 at 60 seconds. Measured agreement was 0.862. Forecast minus measurement was 0.048, with a paired 95% bootstrap interval of -0.005 to 0.109 from 20,000 person draws. The interval included zero. Thus, the main test did not establish the forecast error found in ds004148. It did not establish formula accuracy. Measured agreement increased by 0.092, with interval 0.023 to 0.201. All nine planned secondary checks are reported. Short scores inherited filtering of the full segment. Earlier public results informed question selection. The package preserves 156 spectra, code, source versions and hashes, all draws, results, and instructions. Separate calculations, two fresh raw replays, and an exact analysis repeat passed.

EEG · test-retest reliability · Spearman–Brown forecast · intraclass correlation · posterior alpha power · recording duration · bootstrap interval · OpenNeuro ds007176