condition mean min max ZT0-3 28.963601 28.963601 28.963601 ZT4-7 29.68699 29.68699 29.68699 ZT8-11 29.75009 29.75009 29.75009 ZT12-15 29.6441315 29.6441315 29.6441315 ZT16-19 28.0437135 28.0437135 28.0437135 ZT20-23 31.773871 31.773871 31.773871