condition mean min max ZT0-3 19.070725 15.8827 22.25875 ZT4-7 9.352355 9.352355 9.352355 ZT8-11 4.778565 4.778565 4.778565 ZT12-15 0 0 0 ZT16-19 9.10798 9.10798 9.10798 ZT20-23 13.47335 13.47335 13.47335