condition mean min max ZT0-3 15.100232 15.100232 15.100232 ZT4-7 15.552007499999998 15.552007499999998 15.552007499999998 ZT8-11 14.9582535 14.9582535 14.9582535 ZT12-15 15.226753500000001 15.226753500000001 15.226753500000001 ZT16-19 11.3855235 11.3855235 11.3855235 ZT20-23 10.180468999999999 10.180468999999999 10.180468999999999