3.13 Consider any closed sequential binomial sampling plan with a set B of stopping points, and letB be the setB∪{(x0, y0)} where (x0, y0) is a point not inB that has positive probability of being reached under plan B. Show that the sufficient statistic T = (X, Y ) is not complete for the sampling plan which has B as its set of stopping points. [Hint: For any point (x, y) ∈ B, let N(x, y) and N

(x, y) denote the number of paths to (x, y) when the set of stopping points is B and B

, respectively, and let N(x0, y0)=0, N

(x0, y0) = 1.

Then, the statistic 1 − [N(X, Y )/N

(X, Y )] has expectation 0 under B for all values of p.]