topic Re: Matrix Correlation in SAS/IML Software and Matrix Computations

Matrix Correlation

trash — Tue, 31 Oct 2017 23:24:35 GMT

I have this data set here were the first x is sales, x2=profits, and x3=assets. Measurements are in millions of dollars.

Company X1 X2 X3

General Motors 126,974 4,224 173,297
Ford 96,933 3,835 160,893
Exxon 86,656 3,510 83,219
IBM 63,438 3,758 77,734
General Electric 55,264 3,939 128,344
Mobil 50,976 1,809 39,080
Philip Morris 39,069 2,946 38,528
Chrysler 36,156 359 51,038
Du Pont 35,209 2,480 34,715

I need to import the data manually and then I am asked to manually find correlation matrix using only matrix manipulation. I assume I somehow I use proc IML. If so, I'd have to create 3 matrices, correct? I don't know where to start.

Re: Matrix Correlation

Reeza — Tue, 31 Oct 2017 23:59:26 GMT

You should review how correlation is calculated in your textbook. Then start by searching using ‘SAS IML Correlation’. The answer is fully in the documentation. http://support.sas.com/documentation/cdl/en/imlug/66845/HTML/default/viewer.htm#imlug_genstatexpls_sect003.htm As to separating the data into 3 matrices, if you review how to calculate correlation that should answer your question.

@trash wrote:
I have this data set here were the first x is sales, x2=profits, and x3=assets. Measurements are in millions of dollars.

Company X1 X2 X3
General Motors 126,974 4,224 173,297
Ford 96,933 3,835 160,893
Exxon 86,656 3,510 83,219
IBM 63,438 3,758 77,734
General Electric 55,264 3,939 128,344
Mobil 50,976 1,809 39,080
Philip Morris 39,069 2,946 38,528
Chrysler 36,156 359 51,038
Du Pont 35,209 2,480 34,715

I need to import the data manually and then I am asked to manually find correlation matrix using only matrix manipulation. I assume I somehow I use proc IML. If so, I'd have to create 3 matrices, correct? I don't know where to start.

Re: Matrix Correlation

Rick_SAS — Wed, 01 Nov 2017 11:49:42 GMT

See the article "Compute covariance and correlation matrices," which shows the four steps that you need to perform to compute a correlation matrix from a data matrix. In particular, you do not need to form three matrices. The three variables become three columns in a single data matrix.