condition mean min max ZT0-3 3.712475 3.60811 3.81684 ZT4-7 4.361325 4.361325 4.361325 ZT8-11 6.153684999999999 6.153684999999999 6.153684999999999 ZT12-15 0 0 0 ZT16-19 5.38669 5.38669 5.38669 ZT20-23 5.871265 5.871265 5.871265