condition mean min max ZT0-3 20.439063 20.439063 20.439063 ZT4-7 20.439063 20.439063 20.439063 ZT8-11 20.515922 20.515922 20.515922 ZT12-15 20.0113965 20.0113965 20.0113965 ZT16-19 20.848586500000003 20.848586500000003 20.848586500000003 ZT20-23 19.991442 19.991442 19.991442