condition mean min max ZT0-3 6.760630000000001 5.16965 8.35161 ZT4-7 7.261654999999999 7.261654999999999 7.261654999999999 ZT8-11 4.44252 4.44252 4.44252 ZT12-15 0 0 0 ZT16-19 4.07968 4.07968 4.07968 ZT20-23 4.53037 4.53037 4.53037