condition mean min max ZT0-3 211.705953 211.705953 211.705953 ZT4-7 191.9189625 191.9189625 191.9189625 ZT8-11 190.7195965 190.7195965 190.7195965 ZT12-15 217.12408349999998 217.12408349999998 217.12408349999998 ZT16-19 220.942101 220.942101 220.942101 ZT20-23 271.377345 271.377345 271.377345