condition mean min max ZT0-3 2.6722799999999998 2.6722799999999998 2.6722799999999998 ZT4-7 5.38308 5.38308 5.38308 ZT8-11 4.7757950000000005 4.7757950000000005 4.7757950000000005 ZT12-15 4.519665 4.519665 4.519665 ZT16-19 2.0965599999999998 2.0965599999999998 2.0965599999999998 ZT20-23 4.366063333333334 4.366063333333334 4.366063333333334