condition mean min max ZT0-3 3.768385 3.768385 3.768385 ZT4-7 2.00594 2.00594 2.00594 ZT8-11 4.369300000000001 4.369300000000001 4.369300000000001 ZT12-15 7.903805 7.903805 7.903805 ZT16-19 10.96425 10.96425 10.96425 ZT20-23 8.876465 8.876465 8.876465