condition mean min max ZT0-3 8.5236325 7.213315 9.83395 ZT4-7 4.4465699999999995 4.4465699999999995 4.4465699999999995 ZT8-11 3.09697 3.09697 3.09697 ZT12-15 0 0 0 ZT16-19 5.352175 5.352175 5.352175 ZT20-23 6.020144999999999 6.020144999999999 6.020144999999999