condition mean min max ZT0-3 8.89497 8.89497 8.89497 ZT4-7 4.43912 4.43912 4.43912 ZT8-11 4.917395 4.917395 4.917395 ZT12-15 7.18633 7.18633 7.18633 ZT16-19 13.85335 13.85335 13.85335 ZT20-23 9.955185 9.955185 9.955185