# Question

In Exercise 4.90 let the transmission time be Tt seconds for a packet. If the packet was received incorrectly, then a message is sent back to the transmitter that states that the message was received incorrectly. Let the time for sending such a message be Ti. Assume that if the packet is received correctly that we do not send an acknowledgement. What is the average time for a successful transmission?

## Answer to relevant Questions

Use the characteristic function (or the moment- generating function or the probability-generating function) to show that a Poisson PMF is the limit of a binomial PMF with n approaching infinity and p approaching zero in such ...Find the first three moments of a geometric random variable whose PMF is PN (n) = (1 – p) pn , n = 0,1, 2, … . Find the mean of the random variables described by each of the following probability mass functions: (a) (b) (c) (d) Find the variance and coefficient of skewness for a geometric random variable whose PMF is You may want to use the results of Exercise 4.13. Suppose X is a random variable with an exponential PDF of the form fX(x) = 2e– 2xu(x). A new random variable is created according to the transformation Y = 1 – X. (a) Find the domain for X and Y. (b) Find fY(y)Post your question

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