condition mean min max ZT0-3 6.267105 5.334295 7.199915 ZT4-7 10.479935 10.479935 10.479935 ZT8-11 7.3786249999999995 7.3786249999999995 7.3786249999999995 ZT12-15 0 0 0 ZT16-19 8.707235 8.707235 8.707235 ZT20-23 8.774355 8.774355 8.774355