condition mean min max ZT0-3 26.405875 24.40535 28.4064 ZT4-7 15.9823 15.9823 15.9823 ZT8-11 16.31585 16.31585 16.31585 ZT12-15 0 0 0 ZT16-19 15.773150000000001 15.773150000000001 15.773150000000001 ZT20-23 23.6526 23.6526 23.6526