condition mean min max ZT0-3 1.7124976666666667 0.5223180000000001 2.6740649999999997 ZT4-7 0.5752245 0.5752245 0.5752245 ZT8-11 0.8118895 0.8118895 0.8118895 ZT12-15 1.2529412500000001 1.0564075 1.449475 ZT16-19 1.35688 1.35688 1.35688 ZT20-23 2.074695 2.074695 2.074695