Practice Problems on Covariance Matrix

Problem 1: Given two sets of data points: X = [2, 4, 6, 8, 10] and Y = [1, 3, 5, 7, 9], calculate the covariance between X and Y.

Problem 2: Calculate the covariance matrix for the following dataset:

X1

X2

X3

4

2

0

4

5

6

8

10

12

12`

9

6

Problem 3: Given the covariance matrix:

[Tex]\Sigma = \begin{bmatrix} 4 & -2 & 0 \\ -2 & 3 & 1 \\ 0 & 1 & 5 \\ \end{bmatrix}[/Tex]

Identify the variances and covariances between the variables.

Covariance Matrix

Covariance Matrix is a type of matrix used to describe the covariance values between two items in a random vector. It is also known as the variance-covariance matrix because the variance of each element is represented along the matrix’s major diagonal and the covariance is represented among the non-diagonal elements.

It’s particularly important in fields like data science, machine learning, and finance, where understanding relationships between multiple variables is crucial and comes in handy when it comes to stochastic modeling and principal component analysis.

In this article, we will discuss about various things related to Covariance Matrix such as it’s definition, example, and formula as well.

Table of Content

  • What is Covariance Matrix?
  • Covariance Matrix Example 
  • Covariance Matrix Formula
    • 2 ⨯ 2 Covariance Matrix
    • 3 ⨯ 3 Covariance Matrix
  • How to Find Covariance Matrix?
  • Properties of Covariance Matrix
  • Solved Examples
  • Practice Problems
  • FAQs

Similar Reads

What is Covariance Matrix?

The variance-covariance matrix is a square matrix with diagonal elements that represent the variance and the non-diagonal components that express covariance. The covariance of a variable can take any real value- positive, negative, or zero. A positive covariance suggests that the two variables have a positive relationship, whereas a negative covariance indicates that they do not. If two elements do not vary together, they have a zero covariance....

Covariance Matrix Example

Let’s say there are 2 data sets X = [10, 5] and Y = [3, 9]. The variance of Set X = 12.5 and the variance of set Y = 18. The covariance between both variables is -15. The covariance matrix is as follows:...

Covariance Matrix Formula

The general form of a covariance matrix is given as follows:...

How to Find Covariance Matrix?

The dimensions of a covariance matrix are determined by the number of variables in a given data set. If there are only two variables in a set, then the covariance matrix would have two rows and two columns. Similarly, if a data set has three variables, then its covariance matrix would have three rows and three columns....

Properties of Covariance Matrix

The Properties of Covariance Matrix are mentioned below:...

Solved Examples on Covariance Matrix

Example 1: The marks scored by 3 students in Physics and Biology are given below:...

Practice Problems on Covariance Matrix

Problem 1: Given two sets of data points: X = [2, 4, 6, 8, 10] and Y = [1, 3, 5, 7, 9], calculate the covariance between X and Y....

FAQs on Covariance Matrix

Define Covariance Matrix...

Contact Us