condition mean min max ZT0-3 9.953048 9.953048 9.953048 ZT4-7 8.145945999999999 8.145945999999999 8.145945999999999 ZT8-11 8.464672 8.464672 8.464672 ZT12-15 8.188564 8.188564 8.188564 ZT16-19 8.3348525 8.3348525 8.3348525 ZT20-23 7.613065 7.613065 7.613065