1Which of the following correctly describes a Tensor of rank 0?
A.A Vector
B.A Matrix
C.A Scalar
D.A 3D Array
Correct Answer: A Scalar
Explanation:A tensor of rank 0 is a scalar (a single number). A rank 1 tensor is a vector, and a rank 2 tensor is a matrix.
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2Given two vectors and , what is their dot product ?
A.7
B.11
C.[3, 8]
D.10
Correct Answer: 11
Explanation:The dot product is calculated as .
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3If matrix has dimensions and matrix has dimensions , what are the dimensions of the product matrix ?
A.
B.
C.
D.
Correct Answer:
Explanation:When multiplying a matrix by a matrix, the inner dimensions () must match, and the resulting matrix has the dimensions of the outer values ().
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4Which of the following properties is not necessarily true for matrix multiplication?
A.Associative:
B.Distributive:
C.Commutative:
D.Identity:
Correct Answer: Commutative:
Explanation:Matrix multiplication is generally non-commutative. is rarely equal to , and often is not even defined depending on dimensions.
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5What is the transpose of the row vector ?
A.
B.A column vector
C.A scalar 6
D.An identity matrix
Correct Answer: A column vector
Explanation:Transposing a row vector converts it into a column vector with the same elements.
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6In the equation , what does represent?
A.The Eigenvector
B.The Eigenvalue
C.The Determinant
D.The Gradient
Correct Answer: The Eigenvalue
Explanation:In the eigenvalue equation, is a square matrix, is the eigenvector, and the scalar is the eigenvalue.
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7Which equation is solved to find the eigenvalues of a square matrix ?
A.
B.
C.
D.
Correct Answer:
Explanation:The characteristic equation is used to determine the eigenvalues .
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8If a matrix is a identity matrix, what are its eigenvalues?
A.0, 0, 0
B.1, 2, 3
C.1, 1, 1
D.It has no eigenvalues
Correct Answer: 1, 1, 1
Explanation:An identity matrix scales any vector by 1. Therefore, all its eigenvalues are 1.
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9Geometrically, what happens to an eigenvector when the linear transformation is applied to it?
A.It rotates by 90 degrees.
B.It becomes zero.
C.It gets scaled by a factor of without changing direction (or reversing direction).
D.It becomes orthogonal to the original vector.
Correct Answer: It gets scaled by a factor of without changing direction (or reversing direction).
Explanation:Eigenvectors are vectors that do not change direction during a linear transformation; they are only scaled by the eigenvalue.
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10The sum of the eigenvalues of a matrix is equal to:
A.The determinant of
B.The trace of (sum of diagonal elements)
C.Zero
D.The rank of
Correct Answer: The trace of (sum of diagonal elements)
Explanation:A fundamental property of linear algebra is that the sum of the eigenvalues equals the trace of the matrix.
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11A variable whose value is subject to variations due to chance is known as:
A.A scalar
B.A Random Variable
C.A constant
D.A derivative
Correct Answer: A Random Variable
Explanation:A random variable maps outcomes of a random phenomenon to numbers.
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12Which of the following represents a Discrete Random Variable?
A.The height of a person
B.The temperature outside
C.The number of heads in 10 coin tosses
D.The time taken to run a mile
Correct Answer: The number of heads in 10 coin tosses
Explanation:Discrete random variables take on countable values (like integers). Height, temperature, and time are continuous.
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13For a probability mass function (PMF) , what is the value of ?
A.0
B.0.5
C.1
D.Undefined
Correct Answer: 1
Explanation:The sum of probabilities for all possible outcomes in a discrete distribution must equal 1.
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14The function describing the probability distribution of a continuous random variable is called:
A.Probability Mass Function (PMF)
B.Probability Density Function (PDF)
C.Covariance Matrix
D.Eigenvector
Correct Answer: Probability Density Function (PDF)
Explanation:PDFs describe continuous variables, while PMFs describe discrete variables.
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15What is the expected value (Mean), , of a discrete random variable ?
A.
B.
C.
D.Max()
Correct Answer:
Explanation:The expected value is the weighted average of all possible values, where the weights are their probabilities.
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16The Variance of a random variable , denoted as , is defined as:
A.
B.
C.
D.
Correct Answer:
Explanation:Variance measures the average squared deviation from the mean.
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17If the variance of a dataset is 25, what is the Standard Deviation?
A.625
B.5
C.25
D.50
Correct Answer: 5
Explanation:Standard deviation is the square root of the variance. .
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18Which alternative formula is commonly used to calculate Variance?
A.
B.
C.
D.
Correct Answer:
Explanation:Variance is equal to the expectation of the square minus the square of the expectation.
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19Covariance between two variables and indicates:
A.The exact cause-and-effect relationship.
B.The direction of the linear relationship between variables.
C.The probability of given .
D.The spread of alone.
Correct Answer: The direction of the linear relationship between variables.
Explanation:Positive covariance indicates variables move together; negative covariance indicates they move inversely. It describes linear association.
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20If two random variables and are independent, what is their Covariance?
A.1
B.-1
C.0
D.Infinity
Correct Answer: 0
Explanation:If variables are independent, there is no linear relationship, so their covariance is 0.
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21What is the Joint Probability ?
A.The probability of event X occurring given event Y has occurred.
B.The probability of event X or event Y occurring.
C.The probability that both event X and event Y occur simultaneously.
D.The sum of individual probabilities.
Correct Answer: The probability that both event X and event Y occur simultaneously.
Explanation:Joint probability refers to the intersection of two events, denoted or .
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22Which rule allows us to calculate the Marginal Probability from a joint probability ?
A.Bayes' Theorem
B.Sum Rule (Marginalization)
C.Chain Rule
D.Product Rule
Correct Answer: Sum Rule (Marginalization)
Explanation:Marginal probability is obtained by summing (for discrete) or integrating (for continuous) the joint probability over the other variable(s). .
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23How is Conditional Probability defined mathematically?
A.
B.
C.
D.
Correct Answer:
Explanation:Conditional probability of A given B is the joint probability divided by the probability of the condition B.
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24According to the Chain Rule of probability, can be written as:
A.
B.
C.
D.
Correct Answer:
Explanation:From the definition of conditional probability, , so .
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25What is the formula for Bayes' Theorem?
A.
B.
C.
D.
Correct Answer:
Explanation:Bayes' theorem describes the probability of an event, based on prior knowledge of conditions that might be related to the event.
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26In Bayes' Theorem , what is called?
A.Posterior
B.Prior
C.Likelihood
D.Evidence
Correct Answer: Likelihood
Explanation:The term is the likelihood of the data given the parameters .
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27In Bayes' Theorem, what is ?
A.Likelihood
B.Posterior
C.Prior
D.Marginal
Correct Answer: Prior
Explanation: represents the prior probability, our belief about the parameters before seeing the data.
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28What is the key difference between Likelihood and Probability?
A.They are identical.
B.Probability relates to data given parameters; Likelihood relates to parameters given data.
C.Probability is always greater than Likelihood.
D.Likelihood is for discrete variables only.
Correct Answer: Probability relates to data given parameters; Likelihood relates to parameters given data.
Explanation:We calculate the probability of future data given fixed parameters. We calculate the likelihood of parameters explaining the past observed data.
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29The goal of Maximum Likelihood Estimation (MLE) is to:
A.Minimize the variance.
B.Find the parameter values that maximize the likelihood of the observed data.
C.Calculate the Bayesian posterior.
D.Integrate the area under the curve.
Correct Answer: Find the parameter values that maximize the likelihood of the observed data.
Explanation:MLE seeks the parameters that make the observed data most probable.
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30What represents the rate of change of a function with respect to ?
A.Integral
B.Derivative
C.Eigenvalue
D.Determinant
Correct Answer: Derivative
Explanation:The derivative measures the instantaneous rate of change.
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31What is the derivative of with respect to ?
A.
B.
C.
D.
Correct Answer:
Explanation:This is the power rule of differentiation.
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32If , what is the partial derivative with respect to ()?
A.
B.
C.
D.
Correct Answer:
Explanation:When taking the partial derivative with respect to , is treated as a constant. The derivative of is , and the derivative of is 0.
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33The vector containing all first-order partial derivatives of a scalar function is called the:
A.Hessian
B.Gradient
C.Jacobian
D.Laplacian
Correct Answer: Gradient
Explanation:The gradient () is a vector of partial derivatives pointing in the direction of steepest ascent.
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34Which rule is used to compute the derivative of a composite function ?
A.Product Rule
B.Quotient Rule
C.Chain Rule
D.Sum Rule
Correct Answer: Chain Rule
Explanation:The Chain Rule states that .
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35Given and , the Chain Rule expresses as:
A.
B.
C.
D.
Correct Answer:
Explanation:The derivative of the composite is the product of the derivatives of the nested functions.
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36What is the derivative of the natural logarithm function ?
A.
B.
C.
D.1
Correct Answer:
Explanation:The standard derivative of is .
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37What is the derivative of the sigmoid function in terms of ?
A.
B.
C.
D.
Correct Answer:
Explanation:This is a useful property for backpropagation in neural networks.
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38A matrix of second-order partial derivatives is known as the:
A.Gradient
B.Hessian Matrix
C.Jacobian Matrix
D.Identity Matrix
Correct Answer: Hessian Matrix
Explanation:The Hessian describes the local curvature of a function of many variables.
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39If the gradient of a function at a specific point is the zero vector, , that point is a:
A.Global Maximum
B.Stationary Point (Critical Point)
C.Discontinuity
D.Asymptote
Correct Answer: Stationary Point (Critical Point)
Explanation:A zero gradient indicates a stationary point, which could be a minimum, maximum, or saddle point.
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40In Gradient Descent, the update rule for a parameter with learning rate is:
A.
B.
C.
D.
Correct Answer:
Explanation:We subtract the gradient to move in the direction of steepest descent (to minimize the function).
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41What is the derivative of a constant ?
A.C
B.1
C.0
D.x
Correct Answer: 0
Explanation:The rate of change of a constant value is zero.
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42For a function , what is ?
A.y
B.x
C.1
D.0
Correct Answer: x
Explanation:Treating as a constant, the derivative of with respect to is .
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43Which of the following describes a Convex Function?
A.A function with multiple local minima.
B.A function where a line segment between any two points on the graph lies above or on the graph.
C.A function that is never differentiable.
D.A function with a negative second derivative.
Correct Answer: A function where a line segment between any two points on the graph lies above or on the graph.
Explanation:Convex functions are bowl-shaped and guarantee that any local minimum is a global minimum.
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44What is the Jacobian Matrix used for?
A.Representing all second-order derivatives.
B.Representing all first-order partial derivatives of a vector-valued function.
C.Finding the eigenvalues of a scalar.
D.Calculating the variance.
Correct Answer: Representing all first-order partial derivatives of a vector-valued function.
Explanation:The Jacobian is the matrix of all first-order partial derivatives of a vector function.
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45If events A and B are mutually exclusive, what is ?
A.0.5
B.1
C.0
D.
Correct Answer: 0
Explanation:Mutually exclusive events cannot happen at the same time, so their intersection probability is 0.
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46If and , and A and B are independent, what is ?
A.0.7
B.0.1
C.0.3
D.0
Correct Answer: 0.1
Explanation:For independent events, .
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47What property of the Normal Distribution makes it symmetric?
A.Mean = Median = Mode
B.Variance = 1
C.It is always positive
D.It has a heavy tail
Correct Answer: Mean = Median = Mode
Explanation:In a perfect normal distribution, the center of the curve is where the mean, median, and mode coincide, creating symmetry.
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48What does the term 'i.i.d' stand for in machine learning and statistics?
A.Integrated Independent Data
B.Independent and Identically Distributed
C.Inverse Identity Distribution
D.Iterative Independent Derivative
Correct Answer: Independent and Identically Distributed
Explanation:It assumes samples are drawn independently from the same probability distribution.
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49The derivative of with respect to is:
A.
B.
C.
D.
Correct Answer:
Explanation:The exponential function is unique because it is its own derivative.
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50Given a scalar and vector , the product results in:
A.A scalar
B.A vector scaled by
C.A matrix
D.0
Correct Answer: A vector scaled by
Explanation:Scalar multiplication of a vector changes the magnitude (and direction if negative) but preserves the vector nature.