condition mean min max ZT0-3 16.890507 16.890507 16.890507 ZT4-7 20.683581 20.683581 20.683581 ZT8-11 23.179948 23.179948 23.179948 ZT12-15 19.711458999999998 19.711458999999998 19.711458999999998 ZT16-19 23.994843 23.994843 23.994843 ZT20-23 20.513534 20.513534 20.513534