condition mean min max ZT0-3 21.32465 19.52735 23.12195 ZT4-7 31.81225 31.81225 31.81225 ZT8-11 32.458600000000004 32.458600000000004 32.458600000000004 ZT12-15 0 0 0 ZT16-19 41.5448 41.5448 41.5448 ZT20-23 31.97475 31.97475 31.97475