Say that we want to send a bit X from a transmitter to a receiver. We model X as Bernoulli(1/2). The issue is that each transmitted bit may be corrupted (i.e., flipped from a 0 to 1 or a 1 to a 0) with probability 1/4, independently of other bits. One way to overcome this noise is to repeat transmissions several times and take a majority vote among the received bits. We assume that the bit is repeated three times, and let Y be the number of 1's observed at the receiver. It follows that Y given X = 0 is Binomial(3, 1/4) and Y given X = 1 is Binomial (3,3/4). (a) Write out the joint PMF Px,y(x, y) as a table. (b) Determine the marginal PMF Py(y). (c) Let A = {2,3} and note that if YE A, then the majority of the three transmissions result in a 1 observed at the receiver. Calculate P[YE A].

A First Course in Probability (10th Edition)
10th Edition
ISBN:9780134753119
Author:Sheldon Ross
Publisher:Sheldon Ross
Chapter1: Combinatorial Analysis
Section: Chapter Questions
Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...
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Only a, b, c please!! Thank you!!

Say that we want to send a bit X from a transmitter to a receiver. We model X as Bernoulli(1/2).
The issue is that each transmitted bit may be corrupted (i.e., flipped from a 0 to 1 or a 1 to a 0)
with probability 1/4, independently of other bits. One way to overcome this noise is to repeat
transmissions several times and take a majority vote among the received bits. We assume that
the bit is repeated three times, and let Y be the number of 1's observed at the receiver. It
follows that Y given X = 0 is Binomial(3, 1/4) and Y given X = 1 is Binomial(3,3/4).
(a) Write out the joint PMF Px,y(x, y) as a table.
(b) Determine the marginal PMF Py(y).
(c) Let A
{2,3} and note that if Y ¤ A, then the majority of the three transmissions result
in a 1 observed at the receiver. Calculate P[Y € A].
(d) Determine P[Y € A|X = 1] and P[Y € A|X = 0].
(e) Calculate the probability that this majority vote is correct, P[X = 1|Y € A], and incorrect,
P[X = 0|Y € A].
=
Transcribed Image Text:Say that we want to send a bit X from a transmitter to a receiver. We model X as Bernoulli(1/2). The issue is that each transmitted bit may be corrupted (i.e., flipped from a 0 to 1 or a 1 to a 0) with probability 1/4, independently of other bits. One way to overcome this noise is to repeat transmissions several times and take a majority vote among the received bits. We assume that the bit is repeated three times, and let Y be the number of 1's observed at the receiver. It follows that Y given X = 0 is Binomial(3, 1/4) and Y given X = 1 is Binomial(3,3/4). (a) Write out the joint PMF Px,y(x, y) as a table. (b) Determine the marginal PMF Py(y). (c) Let A {2,3} and note that if Y ¤ A, then the majority of the three transmissions result in a 1 observed at the receiver. Calculate P[Y € A]. (d) Determine P[Y € A|X = 1] and P[Y € A|X = 0]. (e) Calculate the probability that this majority vote is correct, P[X = 1|Y € A], and incorrect, P[X = 0|Y € A]. =
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