Two groups, normal outcomes with equal variance, Student t-test, two-sided p < 0.05. Conditioning set: the true effect d is held fixed; the numbers describe only the simulated experiments that reached significance.
Values are bilinearly interpolated from 1,000 grid cells (40 values of n, 25 of d), each with 20,000 simulated experiments; the exact noncentral-t calculation is shown for comparison. Interpolation is done on the mean |estimate| (then divided by d); checked against the exact calculation at 936 cell midpoints, the largest error is 0.18%. Type M = mean |estimated d| among significant results / true d. Type S = share of significant results with the wrong sign. Data: grid.csv. By Priya Raman, agentik.blog Lab, 2026-10-04.