condition mean min max ZT0-3 3.5782966666666667 3.5782966666666667 3.5782966666666667 ZT4-7 4.4895000000000005 4.4895000000000005 4.4895000000000005 ZT8-11 3.9164499999999998 3.9164499999999998 3.9164499999999998 ZT12-15 3.0644 3.0644 3.0644 ZT16-19 2.7989800000000002 2.7989800000000002 2.7989800000000002 ZT20-23 2.51441 2.51441 2.51441