condition mean min max ZT0-3 3.9458466666666667 1.951 5.557309999999999 ZT4-7 1.42181 1.42181 1.42181 ZT8-11 1.9834100000000001 1.9834100000000001 1.9834100000000001 ZT12-15 6.7704474999999995 5.422775 8.11812 ZT16-19 7.781065 7.781065 7.781065 ZT20-23 7.029325 7.029325 7.029325