condition mean min max ZT0-3 8.271494000499999 7.763858524 8.779129477 ZT4-7 5.278808214 4.965843402 5.591773026 ZT8-11 8.75467146475 7.311016874 10.1983260555 ZT12-15 8.884857128250001 8.695704574 9.0740096825 ZT16-19 10.04668163925 9.9195004645 10.173862814 ZT20-23 10.775783898499999 9.882779166999999 11.66878863