condition mean min max ZT0-3 29.787499999999998 29.787499999999998 29.787499999999998 ZT4-7 23.65505 23.65505 23.65505 ZT8-11 16.68255 16.68255 16.68255 ZT12-15 7.360474999999999 7.360474999999999 7.360474999999999 ZT16-19 20.877433333333332 20.877433333333332 20.877433333333332 ZT20-23 29.7293 29.7293 29.7293