The families in a community are divided into four income groups G x,
G2, G3, G4, consisting of N u N 2, N3, NA families, respectively. Each
group is composite in the sense that it consists of German, English,
Canadian, and American families, their respective proportions for the
group Gj being qn , qj2, qj3, qj4, 2*=i q,k = 1, j = 1,2,3,4. A family is
chosen at random and is found to be German. What is the probability
that it belongs to the group G;?