condition mean min max ZT0-3 22.564811 22.564811 22.564811 ZT4-7 25.6282465 25.6282465 25.6282465 ZT8-11 26.742416 26.742416 26.742416 ZT12-15 27.1944655 27.1944655 27.1944655 ZT16-19 19.501362999999998 19.501362999999998 19.501362999999998 ZT20-23 20.5956825 20.5956825 20.5956825