1model,estimate,se,ci_low,ci_high2unadjusted OLS (training_hours only),-0.13169790632300882,0.014619618827634278,-0.1603518326928757,-0.103043979953141953adjusted OLS (training_hours + skill_index) [main],0.25353820594501253,0.009812212326345536,0.2343066231767153,0.272769788713309764"sensitivity: adjusted, incl. negative-hours rows",0.25222449623309495,0.00947885217664965,0.23364628735208254,0.270802705114107375sensitivity: adjusted + quadratic terms (linear coef),0.24200678175644616,0.02894480910346859,0.18527599837426062,0.29873756513863176"sensitivity: adjusted, conventional SE",0.25353820594501253,0.0098410870694658,0.2342303088883248,0.272846103001700267