condition mean min max ZT0-3 21.326217 21.326217 21.326217 ZT4-7 46.450117 46.450117 46.450117 ZT8-11 81.635425 81.635425 81.635425 ZT12-15 71.449248 71.449248 71.449248 ZT16-19 65.7802945 65.7802945 65.7802945 ZT20-23 61.6532835 61.6532835 61.6532835