condition mean min max ZT0-3 13.291517 13.291517 13.291517 ZT4-7 21.482340999999998 21.482340999999998 21.482340999999998 ZT8-11 18.9095675 18.9095675 18.9095675 ZT12-15 20.0492755 20.0492755 20.0492755 ZT16-19 22.714738 22.714738 22.714738 ZT20-23 20.2897365 20.2897365 20.2897365