condition mean min max ZT0-3 5.698725 5.698725 5.698725 ZT4-7 3.8237500000000004 3.8237500000000004 3.8237500000000004 ZT8-11 4.442155 4.442155 4.442155 ZT12-15 5.437255 5.437255 5.437255 ZT16-19 6.99659 6.99659 6.99659 ZT20-23 6.240775 6.240775 6.240775