condition mean min max ZT0-3 18.079725 17.67285 18.4866 ZT4-7 11.9777 11.9777 11.9777 ZT8-11 12.1684 12.1684 12.1684 ZT12-15 0 0 0 ZT16-19 23.459600000000002 23.459600000000002 23.459600000000002 ZT20-23 23.57785 23.57785 23.57785