condition mean min max ZT0-3 9.67666 7.99692 11.3564 ZT4-7 14.77135 14.77135 14.77135 ZT8-11 17.564999999999998 17.564999999999998 17.564999999999998 ZT12-15 0 0 0 ZT16-19 14.338550000000001 14.338550000000001 14.338550000000001 ZT20-23 13.81605 13.81605 13.81605