Random Signal MCQ [Free PDF] – Objective Question Answer for Random Signal Quiz

1. Random variables give the relationship between _____

A. Two random events
B. Probability of occurrence of two random events
C. Random event and a real number
D. Random event and its probability of occurrence

Answer: C

A random variable gives a functional relationship between a random event and a real number.

 

2. The distribution function of a  random variable is

A. P(X less than or equal to x)
B. P(X greater than or equal to x)
C. P(X less than x)
D. P(X greater than x)

Answer: A

The distribution function of a random variable is the probability that the value taken by the random variable is less than or equal to the real number x.

 

3. The distribution function of -(infinity) and (infinity) is _____

A. 0 and 1
B. 1 and 0
C. Both 0
D. Both 1

Answer: A

The distribution function of -(infinity) and (infinity) is 0 and 1

F(−∞) is 0 and F

(∞)) is 1.

 

4. The value of the probability density function of a  random variable is

A. Positive function
B. Negative function
C. Zero
D. One

Answer: A

The probability density function is always greater than 0. It is a non-negative function with the area of 1.

 

5. Which gives the measure of randomness of the random variable?

A. Mean
B. Variance
C. Standard variance
D. Pdf

Answer: B

Variance gives the randomness of the random variable. It is the difference between the mean square value and the square of the mean.

 

6. Random process is a function of ______

A. Random event and time
B. Random event and frequency
C. Random event and real number
D. None of the mentioned

Answer: A

A random process is a function of two variables: a random event and its time of occurrence.

 

7. A random process is called stationary in the  strict sense if

A. Its statistics vary with shifts in time origin
B. Its statistics do not vary with a  shift in time origin
C. Its autocorrelation varies with a  shift in time
D. Its autocorrelation does not vary with shifts in time

Answer: A

A random process is defined to be stationary in a strict sense if its statistics vary with a shift in time origin.

 

8. For a stationary process, the autocorrelation function depends on

A. Time
B. Time difference
C. Does not depend on the time
D. None of the mentioned

Answer: B

The autocorrelation function depends on the time difference between t1 and t2.

 

9. The autocorrelation function is maximum at

A. Origin
B. Infinity
C. Origin & Infinity
D. None of the mentioned

Answer: A

On substituting different values in the formula for autocorrelation function will be maximum at the origin.

 

10. Standard deviation is ______

A. Rms value of dc
B. Rms value or ac
C. Either ac or dc
D. Neither dc nor ac

Answer: B

The standard deviation of a random variable gives the RMS value of an ac component.

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