condition mean min max ZT0-3 3.348656833333333 1.4656205 4.319595 ZT4-7 1.4002314999999999 1.4002314999999999 1.4002314999999999 ZT8-11 8.042185 8.042185 8.042185 ZT12-15 9.130685000000001 6.908370000000001 11.353000000000002 ZT16-19 3.211795 3.211795 3.211795 ZT20-23 3.958385 3.958385 3.958385