Solved

Determine slope intercept y=mx+b from 2 arrays

Posted on 2013-01-16
3
477 Views
Last Modified: 2013-01-18
Hi All -

Ironically, I'm quite handy with data, but pretty bad at Math.  I'm in the process of building a revenue forecasting tool and have a good way to forecast calls.  What I want to do now is apply a slope intercept formula to forecasted calls to guess how many orders those calls will yield.  

See the attached spreadsheet for an example of what I'm talking about.  You can ignore the formulas as i just used them to generate some example data.  What I really want to understand is how Excel comes up with the y=mx+b formula that it shows on the graph.  

Please explain the math to me as if I were in 6th grade (like i said... not my strong point).  

Also - please don't offer any suggestions on spreadsheet formulas I could use to apply the slope intercept as the tool isn't Excel based.  I just need to understand the "paper and pencil math" so i can re-produce it in-memory
Slope-for-EE.xlsx
0
Comment
Question by:ducky801
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
3 Comments
 
LVL 84

Expert Comment

by:ozo
ID: 38785356
0
 
LVL 12

Accepted Solution

by:
PCableGuy earned 500 total points
ID: 38785378
0
 
LVL 84

Expert Comment

by:ozo
ID: 38785406
Minimizing the sum of the squares of the differences between mx+b and y
gives the maximum likelyhood estimator under the assumption that the y values were produced from mx+b  +  independent Gaussian errors.

Taking the derivatives of the sum of the squares of the differences with respect to m and b
and setting them to 0 finds the minimum.
Each constraint is a linear equation on m and b, and solving them simultaneously gives
the standard formula.
0

Featured Post

PeopleSoft Has Never Been Easier

PeopleSoft Adoption Made Smooth & Simple!

On-The-Job Training Is made Intuitive & Easy With WalkMe's On-Screen Guidance Tool.  Claim Your Free WalkMe Account Now

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This code takes an Excel list of URL’s and adds a header titled “URL List”. It then searches through all URL’s in column “A”, looking for duplicates. When a duplicate is found, it is moved to the top of the list. The duplicate URL’s are then highlig…
How to get Spreadsheet Compare 2016 working with the 64 bit version of Office 2016
This Micro Tutorial will demonstrate the scrolling table in Microsoft Excel using the INDEX function.
This is a video describing the growing solar energy use in Utah. This is a topic that greatly interests me and so I decided to produce a video about it.

627 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question