{"kind":"assistant","text":"att = mean(d | treated) - mean(d | control), se = sqrt(s1/n1 + s0/n0): the slope of d on a treated dummy with HC2 errors is exactly that difference and that unequal-variance SE","tool_calls":[{"args":{"dataset":"ref_diff","se":"HC2","x":["treated"],"y":"d"},"id":"script_1","name":"infer__ols"}]}