condition mean min max ZT0-3 18.664756 18.664756 18.664756 ZT4-7 19.1871495 19.1871495 19.1871495 ZT8-11 18.300167000000002 18.300167000000002 18.300167000000002 ZT12-15 17.0061265 17.0061265 17.0061265 ZT16-19 16.8282945 16.8282945 16.8282945 ZT20-23 21.0363555 21.0363555 21.0363555