condition mean min max ZT0-3 10.718895 9.726510000000001 11.711279999999999 ZT4-7 11.27745 11.27745 11.27745 ZT8-11 23.11965 23.11965 23.11965 ZT12-15 0 0 0 ZT16-19 20.21515 20.21515 20.21515 ZT20-23 15.4697 15.4697 15.4697