condition mean min max ZT0-3 10.414577 10.414577 10.414577 ZT4-7 14.470424999999999 14.470424999999999 14.470424999999999 ZT8-11 15.7721485 15.7721485 15.7721485 ZT12-15 15.0990415 15.0990415 15.0990415 ZT16-19 16.2797335 16.2797335 16.2797335 ZT20-23 12.285176 12.285176 12.285176