# Questions by neha.i

1
Suppose $X$ is distributed as Poisson with mean $λ.$ Then $E(1/(X + 1))$ is $\frac{e^{\lambda }-1}{\lambda }$ $\frac{e^{\lambda }-1}{\lambda +1}$ $\frac{1-e^{-\lambda }}{\lambda}$ $\frac{1-e^{-\lambda }}{\lambda + 1}$
1 vote
Let A be a square matrix such that $A^{3}$ = 0, but $A^{2} \neq 0$. Then which of the following statements is not necessarily true? (A) $A \neq A^{2}$ (B) Eigenvalues of $A^{2}$ are all zero (C) rank(A) > rank($A^{2}$ ) (D) rank(A) > trace(A)
A club with $n$ members is organized into four committees so that each member belongs to exactly two committees and each pair of committees has exactly one member in common. Then $n = 4$ $n = 6$ $n = 8$ $n$ cannot be determined from the given information