condition mean min max ZT0-3 18.81745 17.78555 19.84935 ZT4-7 9.44274 9.44274 9.44274 ZT8-11 11.4729 11.4729 11.4729 ZT12-15 0 0 0 ZT16-19 17.084600000000002 17.084600000000002 17.084600000000002 ZT20-23 17.89235 17.89235 17.89235