condition mean min max ZT0-3 17.24701 17.24701 17.24701 ZT4-7 20.477317 20.477317 20.477317 ZT8-11 18.0116085 18.0116085 18.0116085 ZT12-15 18.3722925 18.3722925 18.3722925 ZT16-19 15.995619999999999 15.995619999999999 15.995619999999999 ZT20-23 13.040145 13.040145 13.040145