Unit 3 - Practice Quiz

ECE180 50 Questions
0 Correct 0 Wrong 50 Left
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1 The expected value of a continuous random variable with probability density function is given by:

A.
B.
C.
D.

2 If is a random variable and is a constant, what is ?

A.
B. $0$
C.
D. $1$

3 Given a random variable and constants and , what is ?

A.
B.
C.
D.

4 If is a function of a continuous random variable , the expected value is calculated as:

A.
B.
C.
D.

5 The -th moment of a random variable about the origin is denoted by and is defined as:

A.
B.
C.
D.

6 The first moment about the origin, , represents the:

A. Variance
B. Mean
C. Kurtosis
D. Skewness

7 The -th central moment is defined as:

A.
B.
C.
D.

8 The second central moment is commonly known as the:

A. Mean
B. Standard Deviation
C. Mean Square Value
D. Variance

9 Which of the following relationships relates the variance , the mean square value , and the mean ?

A.
B.
C.
D.

10 What is the value of the first central moment, ?

A.
B.
C. $1$
D. $0$

11 For a random variable and constants , the variance is equal to:

A.
B.
C.
D.

12 Skewness is a measure of:

A. The asymmetry of the probability distribution
B. The spread of the distribution
C. The central tendency
D. The peakedness of the distribution

13 The coefficient of skewness is defined using the third central moment and standard deviation as:

A.
B.
C.
D.

14 Kurtosis relates to which central moment?

A. Fourth
B. Second
C. First
D. Third

15 If a PDF is symmetric about its mean, then all odd order central moments are:

A. Positive
B. Infinite
C. One
D. Zero

16 Chebyshev's Inequality provides a bound on probability for:

A. Only Normal distributions
B. Only Exponential distributions
C. Only Discrete distributions
D. Any random variable with finite mean and variance

17 According to Chebyshev's Inequality, is less than or equal to:

A.
B.
C.
D.

18 Using Chebyshev's inequality, what is the lower bound for the probability that lies within $2$ standard deviations of the mean ()?

A. $0.95$
B. $0.50$
C. $0.25$
D. $0.75$

19 The Characteristic Function of a random variable is defined as:

A.
B.
C.
D.

20 The value of the characteristic function at the origin, , is always:

A.
B. Undefined
C. $0$
D. $1$

21 The maximum absolute value of the characteristic function is:

A. Equal to variance
B.
C.
D. Infinite

22 If is the characteristic function of , the -th moment of can be found by:

A.
B.
C.
D.

23 The Moment Generating Function (MGF) is defined as:

A.
B.
C.
D.

24 Using the MGF , the -th moment is calculated as:

A.
B.
C.
D.

25 Unlike the characteristic function, the moment generating function:

A. Is always complex-valued
B. Has a maximum value of 0
C. Always exists for all distributions
D. May not exist if the integral diverges

26 If , and is the MGF of , then is:

A.
B.
C.
D.

27 The characteristic function of the sum of two independent random variables is:

A. The product of their characteristic functions
B. The difference of their characteristic functions
C. The convolution of their characteristic functions
D. The sum of their characteristic functions

28 Given a transformation , if is a monotonic differentiable function, the PDF of , , is given by:

A.
B.
C.
D.

29 If and is a continuous random variable, then is:

A.
B.
C.
D.

30 Consider the transformation . If the PDF of is , what is for ?

A.
B.
C.
D.

31 For a linear transformation , the mean is:

A.
B.
C.
D.

32 For a linear transformation , the standard deviation is:

A.
B.
C.
D.

33 If the characteristic function of is , then has which distribution?

A. Exponential
B. Poisson
C. Gaussian (Normal) with mean 0
D. Uniform

34 The second derivative of the Moment Generating Function at yields:

A. Mean Square Value ()
B. Mean
C. Skewness
D. Variance

35 Which inequality states that for a non-negative random variable , ?

A. Markov's Inequality
B. Chebyshev's Inequality
C. Jensen's Inequality
D. Cauchy-Schwarz Inequality

36 If is a discrete random variable with PMF , the expected value is:

A.
B.
C.
D.

37 If the variance of is zero, then:

A. is uniformly distributed
B.
C. is a constant with probability 1
D. does not exist

38 If , how are the characteristic functions related?

A.
B.
C.
D.

39 The Maclaurin series expansion of the Characteristic Function generates coefficients related to:

A. Probabilities
B. Central moments
C. Standard deviation
D. Moments about the origin multiplied by

40 Let be a random variable with mean and variance . Using Chebyshev's inequality, is at most:

A.
B.
C.
D.

41 The characteristic function of a standard normal random variable is:

A.
B.
C.
D.

42 Which property allows us to recover the PDF from the Characteristic Function?

A. Differentiation
B. Inverse Fourier Transform
C. Convolution
D. Integration

43 For a random variable , the quantity is called:

A. Mean
B. Root Mean Square (RMS)
C. Variance
D. Standard Deviation

44 If for , what is ?

A. $0$
B. $1$
C. $2$
D. $0.5$

45 The skewness of the normal distribution is:

A.
B. $1$
C. $0$
D. $3$

46 If is Uniformly distributed in , then follows which distribution?

A. Exponential
B. Normal
C. Rayleigh
D. Uniform

47 The cumulant generating function is defined as:

A.
B.
C.
D.

48 What is the relation between the second cumulant and the variance?

A.
B.
C.
D.

49 If exists, then:

A. Variance is zero
B. and must also exist
C. must also exist
D. The distribution is symmetric

50 For the transformation , where is constant, the PDF is:

A.
B.
C.
D.