condition mean min max ZT0-3 1.555595 1.30546 1.730795 ZT4-7 2.1482599999999996 2.1482599999999996 2.1482599999999996 ZT8-11 1.58234 1.58234 1.58234 ZT12-15 3.2841199999999997 3.08357 3.48467 ZT16-19 4.497395 4.497395 4.497395 ZT20-23 2.73454 2.73454 2.73454