condition mean min max ZT0-3 33.021175 32.0199 34.022450000000006 ZT4-7 19.2182 19.2182 19.2182 ZT8-11 17.654600000000002 17.654600000000002 17.654600000000002 ZT12-15 0 0 0 ZT16-19 35.30805 35.30805 35.30805 ZT20-23 29.9939 29.9939 29.9939