Introductory Econometrics: A Modern Approach 6th Edition by Jeffrey M Wooldridge

Exercise 11

Let X be an n × k matrix partitioned as

 where X₁ is n × k₁ and X₂ is n × k₂.

(i) Show that

What are the dimensions of each of the matrices?

(ii) Let b be a k × 1 vector, partitioned as

where b₁ is k₁ × 1 and b₂ is k₂ × 1. Show that

Step 1 of 3

Consider that matrix X have n rows and k columns. Matrix X is partitioned as below:

Here,