condition mean min max ZT0-3 51.60841666666666 18.5254 68.39025 ZT4-7 16.46715 16.46715 16.46715 ZT8-11 8.873529999999999 8.873529999999999 8.873529999999999 ZT12-15 18.988100000000003 15.77175 22.20445 ZT16-19 27.4062 27.4062 27.4062 ZT20-23 47.75405 47.75405 47.75405