condition mean min max ZT0-3 4.022943333333333 3.58298 4.55064 ZT4-7 4.217835 4.217835 4.217835 ZT8-11 7.064030000000001 7.064030000000001 7.064030000000001 ZT12-15 8.29125 7.64252 8.93998 ZT16-19 7.54136 7.54136 7.54136 ZT20-23 7.779175 7.779175 7.779175