condition mean min max ZT0-3 2.1608116666666666 1.702175 2.86285 ZT4-7 0.837736 0.837736 0.837736 ZT8-11 0.7358665 0.7358665 0.7358665 ZT12-15 1.5948995000000001 1.0440740000000002 2.145725 ZT16-19 1.398245 1.398245 1.398245 ZT20-23 3.422295 3.422295 3.422295