condition mean min max ZT0-3 8.130646 8.130646 8.130646 ZT4-7 7.807926500000001 7.807926500000001 7.807926500000001 ZT8-11 8.059218999999999 8.059218999999999 8.059218999999999 ZT12-15 8.6264855 8.6264855 8.6264855 ZT16-19 7.9819965 7.9819965 7.9819965 ZT20-23 7.9610665 7.9610665 7.9610665