condition mean min max ZT0-3 4.907895 4.907895 4.907895 ZT4-7 8.44628 8.44628 8.44628 ZT8-11 4.24071 4.24071 4.24071 ZT12-15 2.9737400000000003 2.9737400000000003 2.9737400000000003 ZT16-19 3.4438750000000002 3.4438750000000002 3.4438750000000002 ZT20-23 3.9657649999999998 3.9657649999999998 3.9657649999999998