condition mean min max ZT0-3 8.948263 8.948263 8.948263 ZT4-7 8.084124 8.084124 8.084124 ZT8-11 8.441116000000001 8.441116000000001 8.441116000000001 ZT12-15 8.0344475 8.0344475 8.0344475 ZT16-19 8.557791000000002 8.557791000000002 8.557791000000002 ZT20-23 8.573861 8.573861 8.573861