condition mean min max ZT0-3 12.5062 11.73265 13.27975 ZT4-7 18.3131 18.3131 18.3131 ZT8-11 28.465649999999997 28.465649999999997 28.465649999999997 ZT12-15 0 0 0 ZT16-19 21.8643 21.8643 21.8643 ZT20-23 17.969549999999998 17.969549999999998 17.969549999999998