condition mean min max ZT0-3 180.101886 180.101886 180.101886 ZT4-7 250.4277835 250.4277835 250.4277835 ZT8-11 259.1904755 259.1904755 259.1904755 ZT12-15 209.36972500000002 209.36972500000002 209.36972500000002 ZT16-19 165.6343195 165.6343195 165.6343195 ZT20-23 111.490895 111.490895 111.490895