condition mean min max ZT0-3 1.593788 0.898679 2.068365 ZT4-7 0.850371 0.850371 0.850371 ZT8-11 2.331335 2.331335 2.331335 ZT12-15 7.1075925 5.72667 8.488515 ZT16-19 6.46668 6.46668 6.46668 ZT20-23 6.14058 6.14058 6.14058