condition mean min max ZT0-3 30.951475 29.592399999999998 32.31055 ZT4-7 19.184150000000002 19.184150000000002 19.184150000000002 ZT8-11 15.78095 15.78095 15.78095 ZT12-15 0 0 0 ZT16-19 25.4969 25.4969 25.4969 ZT20-23 33.46925 33.46925 33.46925