condition mean min max ZT0-3 2.10757 2.10757 2.10757 ZT4-7 2.1377 2.1377 2.1377 ZT8-11 1.593565 1.593565 1.593565 ZT12-15 2.04934 2.04934 2.04934 ZT16-19 2.561645 2.561645 2.561645 ZT20-23 1.9614150000000001 1.9614150000000001 1.9614150000000001