condition mean min max ZT0-3 6.4352908555 5.8377155179999995 7.032866193 ZT4-7 6.277041794333333 5.262580578333333 7.291503010333333 ZT8-11 5.814730385833334 5.7576596 5.871801171666667 ZT12-15 8.2705264665 7.56401262 8.977040313 ZT16-19 8.5877190435 7.6707813510000005 9.504656736 ZT20-23 6.265784307166667 6.024723377 6.506845237333334