condition mean min max ZT0-3 3.5207719194999996 3.2614904819999997 3.780053357 ZT4-7 2.6030652002499997 2.2441652125 2.9619651879999997 ZT8-11 2.562723211 2.4628190804999996 2.6626273415 ZT12-15 1.9187258052499998 1.719013262 2.1184383485 ZT16-19 3.3671651557500004 2.3515163045 4.382814007 ZT20-23 5.89289859025 5.762582688 6.023214492499999