condition mean min max ZT0-3 1.4317916666666668 1.258585 1.6041850000000002 ZT4-7 1.58364 1.58364 1.58364 ZT8-11 1.746345 1.746345 1.746345 ZT12-15 4.103485 3.55358 4.65339 ZT16-19 3.430295 3.430295 3.430295 ZT20-23 2.142935 2.142935 2.142935