# Excel Datamining Linear Regression Coeffiecents within the SQL Datamining addin

### Question

• When I create an advanced mining structure and a linear regression to the structure, initially I get a "browse" summary with a graph as well as a histogram. Beneath the histogram there is a an equation that gives the factors and the coeffiecents. These numbers are different than what is provided when I go to the "model usage" tab and document model. Any clue what the difference in equations is from? Is it in sample vs total population?

Tom

Wednesday, July 09, 2014 9:42 PM

### All replies

• Hi,

This is the forum to discuss questions and feedback for Microsoft Excel ,the issue is more related to Data Mining Add-ins, I'll move your question to the Data Mining forum

http://social.technet.microsoft.com/Forums/sqlserver/en-US/home?forum=sqldatamining

The reason why we recommend posting appropriately is you will get the most qualified pool of respondents, and other partners who read the forums regularly can either share their knowledge or learn from your interaction with us. Thank you for your understanding.

George Zhao
TechNet Community Support

Thursday, July 10, 2014 6:50 AM
• Do you see big difference in the numbers?

If I remember correctly, "Document Model" is making some changes to make the formula look better.

y= a1*(x1-c1) + a2*(x2-c2) + a3*(x3-c3) is replaced with

y=a1'*x1+a2'*x2+a3'*x3+c4 where

a1' is rounded value of a1 and c4=a1*c1+a2*c2+a3*c3

If you need more help, please post to formulas that you see in both places.

Tatyana Yakushev [PredixionSoftware.com]

Thursday, July 10, 2014 5:25 PM