condition mean min max ZT0-3 5.1334599999999995 5.1334599999999995 5.1334599999999995 ZT4-7 5.445675 5.445675 5.445675 ZT8-11 6.52158 6.52158 6.52158 ZT12-15 8.02882 8.02882 8.02882 ZT16-19 8.05931 8.05931 8.05931 ZT20-23 6.26477 6.26477 6.26477