condition mean min max ZT0-3 3.6616225 2.900905 4.42234 ZT4-7 4.32618 4.32618 4.32618 ZT8-11 3.5498450000000004 3.5498450000000004 3.5498450000000004 ZT12-15 0 0 0 ZT16-19 7.913335 7.913335 7.913335 ZT20-23 9.251975 9.251975 9.251975