condition mean min max ZT0-3 3.7642275 3.7467449999999998 3.7817100000000003 ZT4-7 3.21884 3.21884 3.21884 ZT8-11 2.963045 2.963045 2.963045 ZT12-15 0 0 0 ZT16-19 4.807815 4.807815 4.807815 ZT20-23 4.119125 4.119125 4.119125