condition mean min max ZT0-3 1.3078396666666667 1.178288 1.43096 ZT4-7 0.814444 0.814444 0.814444 ZT8-11 1.368472 1.368472 1.368472 ZT12-15 0.7238089999999999 0.6657379999999999 0.78188 ZT16-19 0.4851285 0.4851285 0.4851285 ZT20-23 0.329529 0.329529 0.329529