MATHEMATICAL EXPECTATION LOF DISCRETE RANDOM VARIABLE X DISTRIBUTED ) ACCORDING TO POISSON'S LAW, IS EQUAL . TO Select one: E(X)=lambda ^x E(X)=lambda E(X)=npq E(X)=e E(X)=e^lambda

The correct answer is: $E(X)=\lambda$<br /><br />Explanation: The mathematical expectation (or mean) of a discrete random variable X distributed according to Poisson's law is equal to the parameter λ (lambda). Poisson distribution is a discrete probability distribution that describes the probability of a given number of events occurring in a fixed interval of time or space, given a known average rate of occurrence. The parameter λ represents the average rate of occurrence of events. Therefore, the mathematical expectation of X is equal to λ.