condition mean min max ZT0-3 11.601618 11.601618 11.601618 ZT4-7 11.8910575 11.8910575 11.8910575 ZT8-11 11.160236999999999 11.160236999999999 11.160236999999999 ZT12-15 9.811959 9.811959 9.811959 ZT16-19 11.5857205 11.5857205 11.5857205 ZT20-23 10.368245 10.368245 10.368245