## Linear regression - extracting info using matrix algebra

### Daniel Miller (view profile)

on 12 Oct 2019
Latest activity Commented on by Daniel Miller

on 12 Oct 2019

### Stephan (view profile)

Hello!
I have a preloaded data which contains four columns and each column contains the following data in the following order:
1. Income (dollars)
2. Education
3. A dummy variable, 1 for male and 0 for female
4. Another dummy variable, 1 for STEM and 0 for not STEM
I've been given the linear model:
INCOME = α + β1EDUCATION + β2MALE + β3STEM
I should answer the following questions:
a) How large is α in the above equation
b) How many dollars greater is the salary of a male than the salary of a female
From what I understand, I should start with storing each column in the data in separate variables. How would I do this?
Any hints to get me started with this task are appreciated!

### Stephan (view profile)

on 12 Oct 2019
Edited by Stephan

### Stephan (view profile)

on 12 Oct 2019

add a column of ones to your matrix DATA in pos. 4. isolate income as a column vector and remove this column from DATA then use:
X = DATA\INCOME
you get the beta values (1-3) and the last one is alpha.
Also possible:
DATA = [DATA ones(size(DATA,1),1]
vals = DATA(:,2:end)\DATA(:,1)
The other stuff should be not a problem by using logical indexing.

Daniel Miller

### Daniel Miller (view profile)

on 12 Oct 2019
Thank you so much! I'll try to solve as much as I can on my own from here on.
Stephan

### Stephan (view profile)

on 12 Oct 2019
Did you notice that you can accept and or vote for useful answers? If you have more problems come back with a new question.
Daniel Miller

### Daniel Miller (view profile)

on 12 Oct 2019
Cheers, I forgot to do that!