condition mean min max ZT0-3 394.385903 394.385903 394.385903 ZT4-7 281.3029395 281.3029395 281.3029395 ZT8-11 172.2415905 172.2415905 172.2415905 ZT12-15 270.65533300000004 270.65533300000004 270.65533300000004 ZT16-19 129.633212 129.633212 129.633212 ZT20-23 237.5367355 237.5367355 237.5367355