condition mean min max ZT0-3 11.889999999999999 11.889999999999999 11.889999999999999 ZT4-7 6.6277777780000005 6.6277777780000005 6.6277777780000005 ZT8-11 7.773888888666667 7.773888888666667 7.773888888666667 ZT12-15 6.572222222 6.572222222 6.572222222 ZT16-19 8.291111111 8.291111111 8.291111111 ZT20-23 6.480000000333333 6.480000000333333 6.480000000333333