condition mean min max ZT0-3 4.414384999999999 4.414384999999999 4.414384999999999 ZT4-7 4.11359 4.11359 4.11359 ZT8-11 2.8763050000000003 2.8763050000000003 2.8763050000000003 ZT12-15 3.025975 3.025975 3.025975 ZT16-19 3.9374199999999995 3.9374199999999995 3.9374199999999995 ZT20-23 3.27691 3.27691 3.27691