condition mean min max ZT0-3 1.7334883333333333 1.56622 2.05056 ZT4-7 1.060479 1.060479 1.060479 ZT8-11 1.4236 1.4236 1.4236 ZT12-15 2.1026775 2.01377 2.191585 ZT16-19 1.4934850000000002 1.4934850000000002 1.4934850000000002 ZT20-23 1.8691 1.8691 1.8691