condition mean min max ZT0-3 8.637777777666667 8.637777777666667 8.637777777666667 ZT4-7 7.9799999999999995 7.9799999999999995 7.9799999999999995 ZT8-11 8.452222222333333 8.452222222333333 8.452222222333333 ZT12-15 5.328888889 5.328888889 5.328888889 ZT16-19 6.902222222 6.902222222 6.902222222 ZT20-23 7.73 7.73 7.73