condition mean min max ZT0-3 1.3986431666666665 1.1077545 1.789045 ZT4-7 1.093185 1.093185 1.093185 ZT8-11 1.4632800000000001 1.4632800000000001 1.4632800000000001 ZT12-15 3.77214 3.54552 3.99876 ZT16-19 3.0953 3.0953 3.0953 ZT20-23 2.6565700000000003 2.6565700000000003 2.6565700000000003