condition mean min max ZT0-3 4.049799999999999 2.51341 4.821565 ZT4-7 3.013095 3.013095 3.013095 ZT8-11 5.221690000000001 5.221690000000001 5.221690000000001 ZT12-15 5.7577324999999995 5.08871 6.426755 ZT16-19 6.03393 6.03393 6.03393 ZT20-23 6.315205000000001 6.315205000000001 6.315205000000001