1.46 Seven balls are distributed randomly into seven cells. Let X, = the number of cells containing exactly i balls. What is the probability distribution of X3? (That is, find P(X3 = r) for every possible z.)For X", = 2, the pattern becomes 3 ball in one cell, 3 ball in another cell and 1 ball in the other cell. The pattern is 331. The number of sample points with this pattern is: 7 1x 71x 41 5 = 14700