condition mean min max ZT0-3 226.432259 226.432259 226.432259 ZT4-7 262.10274300000003 262.10274300000003 262.10274300000003 ZT8-11 336.3313795 336.3313795 336.3313795 ZT12-15 305.251805 305.251805 305.251805 ZT16-19 451.0581475 451.0581475 451.0581475 ZT20-23 422.19820949999996 422.19820949999996 422.19820949999996