condition mean min max ZT0-3 23.485275 21.8408 25.12975 ZT4-7 20.9158 20.9158 20.9158 ZT8-11 20.736800000000002 20.736800000000002 20.736800000000002 ZT12-15 0 0 0 ZT16-19 22.06915 22.06915 22.06915 ZT20-23 23.746850000000002 23.746850000000002 23.746850000000002