condition mean min max ZT0-3 16.639899999999997 16.43405 16.84575 ZT4-7 18.79655 18.79655 18.79655 ZT8-11 19.52355 19.52355 19.52355 ZT12-15 0 0 0 ZT16-19 24.056150000000002 24.056150000000002 24.056150000000002 ZT20-23 19.9736 19.9736 19.9736