condition mean min max ZT0-3 20.144624999999998 19.77055 20.5187 ZT4-7 17.74635 17.74635 17.74635 ZT8-11 16.64585 16.64585 16.64585 ZT12-15 0 0 0 ZT16-19 22.0332 22.0332 22.0332 ZT20-23 22.18855 22.18855 22.18855