condition mean min max ZT0-3 9.466078333333334 8.92688 9.857695 ZT4-7 7.917445 7.917445 7.917445 ZT8-11 4.99142 4.99142 4.99142 ZT12-15 6.11098 5.412675 6.809285 ZT16-19 5.2707049999999995 5.2707049999999995 5.2707049999999995 ZT20-23 9.00549 9.00549 9.00549