condition mean min max ZT0-3 10.968466 10.968466 10.968466 ZT4-7 11.8851505 11.8851505 11.8851505 ZT8-11 12.891822000000001 12.891822000000001 12.891822000000001 ZT12-15 12.058806 12.058806 12.058806 ZT16-19 12.406134 12.406134 12.406134 ZT20-23 12.608573 12.608573 12.608573