condition mean min max ZT0-3 14.746675 13.9375 15.55585 ZT4-7 10.6716 10.6716 10.6716 ZT8-11 9.818294999999999 9.818294999999999 9.818294999999999 ZT12-15 0 0 0 ZT16-19 11.8973 11.8973 11.8973 ZT20-23 10.251155 10.251155 10.251155