100% satisfaction guarantee Immediately available after payment Both online and in PDF No strings attached
logo-home
Summary Introduction to Multivariate Statistics - FEB22003X $5.89   Add to cart

Summary

Summary Introduction to Multivariate Statistics - FEB22003X

 7 views  0 purchase
  • Course
  • Institution
  • Book

Since the Introduction to Multivariate Statistics (FEB22003X) is an open book exam, this summary note can help a lot. It contains all the tutorial solutions + intuition behind the contents.

Preview 4 out of 70  pages

  • Yes
  • October 24, 2023
  • 70
  • 2023/2024
  • Summary
avatar-seller
Multivariate Statistics

Hyunmin Hong

October 18, 2023




1

,Contents
1 Lecture 1 4
1.1 Distance & Statistical Distance . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.2 Statistical Distance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2 Lecture 2 6
2.1 Random Vectors & Random Matrices . . . . . . . . . . . . . . . . . . . . . . 6
2.2 Linear Combination of Random Vectors . . . . . . . . . . . . . . . . . . . . . 7
2.2.1 Univariate case . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2.2 Multivariate case . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3 Lecture 3 8
3.1 Geometry of a Sample . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.2 Geometric Interpretation of Average . . . . . . . . . . . . . . . . . . . . . . . 8
3.2.1 Deviation Vectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.3 Estimation of µ & Σ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

4 Lecture 4 12
4.1 Generalized Variance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.1.1 Generalized Variance in p dimensions . . . . . . . . . . . . . . . . . . 13
4.2 Geometric Interpretation of Statistical Distance . . . . . . . . . . . . . . . . . 14
4.3 Geometric Intuition of Covariance Matrix . . . . . . . . . . . . . . . . . . . . 15

5 Lecture 5 16
5.1 Multivariate Normal Distribution . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.1.1 Properties of Multivariate Normal Distribution . . . . . . . . . . . . . 17

6 Lecture 6 22
6.1 Estimation (by Maximum Likelihood) . . . . . . . . . . . . . . . . . . . . . . 22
6.1.1 Maximum Likelihood Estimates . . . . . . . . . . . . . . . . . . . . . . 22

7 Lecture 7 23
7.1 MLE of Multivariate Normal Distribution . . . . . . . . . . . . . . . . . . . . 23
7.1.1 Remarks about MLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
7.1.2 What is the distribution of µ̂M LE & Σ̂M LE ? . . . . . . . . . . . . . . 26

8 Lecture 8 27
8.1 Asymptotic Behavior of µ̂M LE & Σ̂M LE . . . . . . . . . . . . . . . . . . . . . 27
8.2 Data Inspection and Distributional Assumptions Check . . . . . . . . . . . . 27
8.2.1 Transformations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
8.3 Multivariate Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
8.3.1 Univariate Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
8.3.2 Multivariate Tests (of location, µ) . . . . . . . . . . . . . . . . . . . . 29

9 Lecture 9 30
9.1 Invariance Property of Hotelling’s T 2 . . . . . . . . . . . . . . . . . . . . . . . 30
9.2 Likelihood Ratio Tests (LRT) . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
9.3 Equivalence of Hotelling’s T 2 & Wilks’ Lambda . . . . . . . . . . . . . . . . . 32

10 Lecture 10 33
10.1 Confidence Regions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33



2

, 10.2 Simultaneously Valid Confidence Intervals . . . . . . . . . . . . . . . . . . . . 33
10.2.1 Correction for Simultaneous Validity . . . . . . . . . . . . . . . . . . . 34
10.2.2 Simultaneously Valid Individual Confidence Intervals . . . . . . . . . . 34
10.3 Bonferroni Correction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
10.4 Asymptotic Approximation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

11 Lecture 11 37
11.1 Principal Component Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . 37
11.1.1 Properties & Interpretation of principal components . . . . . . . . . . 38

12 Lecture 12 40
12.1 Principal Component Analysis (continued) . . . . . . . . . . . . . . . . . . . . 40
12.1.1 Principal components are not scale invariant . . . . . . . . . . . . . . 40
12.1.2 Special Cases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
12.1.3 How many principal components to retain? . . . . . . . . . . . . . . . 42
12.2 Factor Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

13 Lecture 13 44
13.1 Factor Analysis (continued) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
13.1.1 Estimation of L & Ψ . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
13.1.2 Estimation of Factor Scores . . . . . . . . . . . . . . . . . . . . . . . . 46
13.1.3 How to choose # of factors? . . . . . . . . . . . . . . . . . . . . . . . . 47




3

, 1 Lecture 1
1.1 Distance & Statistical Distance
Definition 1.1. Distance is a function defined on M .

d(x, y) : M × M → R

such that
a) d(x, y) ≥ 0, d(x, y) = 0 if x = y.
b) d(x, y) = d(y, x) (symmetry)
c) d(x, z) ≤ d(x, y) + d(y, z) (triangle inequality)
Example 1.1 (Euclidean distance).
p
d(x, y) = (x1 − y1 )2 + (x2 − y2 )2


Example 1.2 (Manhattan distance).

d(x, y) = |x1 − y1 | + |x2 − y2 |



1.2 Statistical Distance




Intuition. You might think that the red square is more extreme from the mean value
than blue square since it does not fall within the cloud of points. However, their Euclidean
distances are equal. Hence, we must take the variance into account when the cloud of
points is distributed in ellipse shape.




4

The benefits of buying summaries with Stuvia:

Guaranteed quality through customer reviews

Guaranteed quality through customer reviews

Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.

Quick and easy check-out

Quick and easy check-out

You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.

Focus on what matters

Focus on what matters

Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!

Frequently asked questions

What do I get when I buy this document?

You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.

Satisfaction guarantee: how does it work?

Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.

Who am I buying these notes from?

Stuvia is a marketplace, so you are not buying this document from us, but from seller hyunminhong. Stuvia facilitates payment to the seller.

Will I be stuck with a subscription?

No, you only buy these notes for $5.89. You're not tied to anything after your purchase.

Can Stuvia be trusted?

4.6 stars on Google & Trustpilot (+1000 reviews)

67474 documents were sold in the last 30 days

Founded in 2010, the go-to place to buy study notes for 14 years now

Start selling
$5.89
  • (0)
  Add to cart