condition mean min max ZT0-3 9.166755 9.166755 9.166755 ZT4-7 10.571494 10.571494 10.571494 ZT8-11 8.326473 8.326473 8.326473 ZT12-15 8.814753 8.814753 8.814753 ZT16-19 8.8362585 8.8362585 8.8362585 ZT20-23 8.736968999999998 8.736968999999998 8.736968999999998