condition mean min max ZT0-3 6.951561666666667 6.264625 7.42598 ZT4-7 8.0254 8.0254 8.0254 ZT8-11 9.653305 9.653305 9.653305 ZT12-15 11.8127725 9.016945 14.6086 ZT16-19 7.665455 7.665455 7.665455 ZT20-23 8.698795 8.698795 8.698795