condition mean min max ZT0-3 6.6516275 6.5165500000000005 6.7867049999999995 ZT4-7 5.13178 5.13178 5.13178 ZT8-11 8.424715 8.424715 8.424715 ZT12-15 0 0 0 ZT16-19 8.92312 8.92312 8.92312 ZT20-23 7.57719 7.57719 7.57719