Data Science 1 Final Exam Multiple Choice

Data Science Exam

• The exam consists of 10 multiple-choice questions in English, with a total of 20 points.
• Submission deadline is 12 June, 2024.

Vectors

• Vectors are not broken into large lists or 1-dimensional arrays.
• A vector is defined as an object with both magnitude and direction.
• Vectors can be broken down into components, which are individual members of the vector.

Vectors and Matrices

• A matrix is not a 1-dimensional array, but rather a 2-dimensional representation of arrays of numbers.
• A matrix with the same number of rows and columns is called a square matrix.
• To represent data in multiple dimensions, we can extend our notion of an array by using a matrix.

Arithmetic Symbols

• The ∑ symbol is used for addition, not proportion.
• In proportion, values can vary directly or indirectly.
• The ∝ symbol represents values that are proportional to each other.
• The right side of the ∑ symbol is usually something iterable.

Graphs

• An exponent tells you how many times you have to multiply a number to itself.
• In graphs, the x variable is the independent variable, and the y variable is the dependent variable.
• The slope defines the rate of change among a large number of points.
• Exponents and logarithms can help model growth or decline.

Set Theory

• Set theory involves mathematical operations, not logarithmic level operations.
• A set is a collection of similar objects.
• An array in Python is not a set, but rather a list of key-indexed pairs.
• A set can be thought of as a list in Python, but with no repeat objects.

Set Theory (continued)

• The magnitude of a set is the number of elements in the set.
• To denote that an element is within a set, use the ∈ symbol, not ∩.
• A ⊆ B means A is a subset of B, and B is called the superset of A.
• If A is a subset of B but A equals B, then A is called a proper subset of B.

Matrix Multiplication Rules

• Matrix multiplication is not commutative.
• You can multiply matrices together if the second number in the first dimension pair is the same as the first number in the second dimension pair.
• In order to multiply matrices, their dimensions do not have to match up.
• The resulting matrix will usually have dimensions equal to the outer numbers in the dimension pairs.

Comparing Vectors in R

• You can compare a vector against a single scalar.
• The comparison operators (==, !=, <, >) can perform an element-by-element comparison of two vectors.
• The comparison operators can also compare a vector's element against a scalar.
• R's two logical values, TRUE and FALSE, are often called Boolean values in Python.

Extracting Vector Elements

• You can use positive indexes to select elements.
• You can use negative indexes to exclude elements.
• You can use parentheses to select vector elements by their position.
• You cannot use matrix multiplication to select elements based on a condition.

Probability Definition

• A procedure is not an act that leads to a result, but rather an act that produces outcomes.
• An event is a collection of the outcomes of a procedure.
• A simple event is an outcome/event of a procedure that cannot be broken down further.
• The two-dimensional space of a procedure is the set of all possible outcomes.

Multiple choice questions for the final examination of Data Science 1 course at Kwangwoon University, covering data analysis concepts.