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C
HAPTER
4
1. For a constant
c
and a random variable
X
, what is the mean of
X
+
c
?
(a)
c
(b)
E[
X
]+
c
(c)
E[
X
]
(d)
c
E[
X
]
2. For two independent random variables
X
and
Y
, what is the mean of
X
+
Y
?
(a)
0
(b)
E[
X
]+E[
Y
]
(c)
E[
X
]E[
Y
]
(d)
None of the above.
3. For two correlated random variables
X
and
Y
, what is the mean of
X
+
Y
?
(a)
0
(b)
E[
X
]+E[
Y
]
(c)
E[
X
]E[
Y
]
(d)
None of the above.
4. For two independent random variables
X
and
Y
, what is the variance of
X
+
Y
?
(a)
0
(b)
var[
X
]+var[
Y
]
(c)
var[
X
]var[
Y
]
(d)
None of the above.
5. For two correlated random variables
X
and
Y
, what is the variance of
X
+
Y
?
(a)
0
(b)
var[
X
]+var[
Y
]
(c)
var[
X
]var[
Y
]
(d)
None of the above.
6. The total area under the pdf curve is
(a)
1
(b)
0
(c)
depends on the nature of the pdf
(d)
none of the above
7. The spectral density of white noise
(a)
varies with frequency
(b)
varies with bandwidth
(c)
varies with amplitude of the signal
(d)
is constant
8. Events
A
and
B
are statistically independent if
(a)
A
and
B
occur simultaneously
(b)
A
and
B
occur at different times
(c)
occurrence of
A
includes that of
B
(d)
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This note was uploaded on 01/11/2011 for the course EE 3008 taught by Professor Pingli during the Fall '08 term at City University of Hong Kong.
 Fall '08
 PingLi

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