condition mean min max ZT0-3 8.446746 8.446746 8.446746 ZT4-7 8.8223015 8.8223015 8.8223015 ZT8-11 8.3685455 8.3685455 8.3685455 ZT12-15 8.553023 8.553023 8.553023 ZT16-19 7.944234 7.944234 7.944234 ZT20-23 8.446746 8.446746 8.446746