condition mean min max ZT0-3 17.510675 12.59205 22.429299999999998 ZT4-7 15.574550000000002 15.574550000000002 15.574550000000002 ZT8-11 14.808 14.808 14.808 ZT12-15 0 0 0 ZT16-19 20.847749999999998 20.847749999999998 20.847749999999998 ZT20-23 26.6403 26.6403 26.6403