GATE PYQ

Multiple Choice (MCQ)1 Mark
Q1.

XX and YY are Bernoulli random variables taking values in {0,1}\{0,1\}. The joint probability mass function of the random variables is given by:

P(X=0,Y=0)=0.06P(X=0,Y=0)=0.06

P(X=0,Y=1)=0.14P(X=0,Y=1)=0.14

P(X=1,Y=0)=0.24P(X=1,Y=0)=0.24

P(X=1,Y=1)=0.56P(X=1,Y=1)=0.56

The mutual information I(X;Y)I(X;Y) is ______ (rounded off to two decimal places).

0.00[c]

1.00

0.50

0.25

1

1/3

mcq

Computer Science And Engineering

Engineering Mathematics

The mutual information is calculated using:

I(X;Y)=p(x,y)log2p(x,y)p(x)p(y)I(X;Y)=\sum p(x,y)\log_2\frac{p(x,y)}{p(x)p(y)}

Marginal probabilities:

P(X=0)=0.2P(X=0)=0.2, P(X=1)=0.8P(X=1)=0.8

P(Y=0)=0.3P(Y=0)=0.3, P(Y=1)=0.7P(Y=1)=0.7

For every combination:

p(x,y)p(x)p(y)=1\frac{p(x,y)}{p(x)p(y)}=1

Therefore,

log2(1)=0\log_2(1)=0

Hence all terms become zero and:

I(X;Y)=0.00I(X;Y)=0.00
A
0.00
B
1.00
C
0.50
D
0.25
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