condition mean min max ZT0-3 20.919975 15.8231 26.016849999999998 ZT4-7 9.567744999999999 9.567744999999999 9.567744999999999 ZT8-11 4.88922 4.88922 4.88922 ZT12-15 0 0 0 ZT16-19 8.037055 8.037055 8.037055 ZT20-23 10.4981 10.4981 10.4981