linear Eqation

[kvic]

I have data and have created a line chart. I add a linear trendline with the Display Equation on chart and display R squared value
Could some help me understand this information.

The chart displays the trendline and I believe I need to know when the data line is under the trendline so I can add stock and let supplies go over the trendline?

y = 0.1014x + 23.077Rē = 0.9775

This is the formula, not having any math skills could someone explain how to use this information

Thanks

[MarvinP]

Hi kvic and welcome to the forum,

Least Squares Regression Lines were developed because people couldn't deal with points above and below a line both. They took a set of points and tried to draw a straight line through all the points. All the points didn't fall on a straight line so they took the distance SQUARED between the point and the line and added up the sum of all these distances (squared) and moved the line around so this sum would be a minimum. This is the name of the line. Least (means the minimum sum of distances of the square of the distances (so they are all positive values as squaring something always is positive)) Regression (no idea why this word is hear) Line (straight line in your case.

Now after you get this line the R Squared number tells how well the line fit all those points. If the R-Squared number is 1 then all the points are EXACTLY on the line. If the R-Squared number is zero then it is a complete random line. Your number of .97 says that the line is a pretty good fit for all those points.

I hope that helps... See http://en.wikipedia.org/wiki/R-squared for more info.

[kvic]

Hi MarvinP

Thanks for your detail response.
I understand the r-Squared value but this doesn't work for me. This value suggests that the data is somewhat deducible. But below is a data row of a product that is incremented each moment in time or not, which is monthly.
From the data, a calculation can be made on how many months, years, seasons and much more from the present are involve in a 99 data points.

14 14 14 14 14 14 14 14 14 14 15 15 15 15 16 16 17 17 17 17 17 17 17 17 17 17 17 17 17 17 18 18 18 18 18 18 18 18 18 18 18 18 19 19 19 19 20 20 20 20 20 20 20 20 21 21 21 21 21 21 21 21 22 22 22 22 22 22 22 22 22 22 22 22 22 22 22 22 22 22 23 23 24 24 24 24 24 24 25 25 25 25 25 25 25 25 25 25 25
The purpose of the chart is to have a visual aid to display the data and I can see that I find it difficult to apprehend a pattern of when to increase or decrease levels of product.

As I understand it from what you are saying, the line displayed over the data points will change whenever new data is added to reflect the new center determined by the data points.

What I would like to know about is the other value y = 0.1014x + 23.077 and how this is used and whether this is a useful calculation?

Maybe you have a better suggestion of a calculation that I should look at?

What I think I am looking for is a weighting I call it that shows that a product is overdue, due or saturated.

Can I use the y calculation to show the least max, min and average values? Just as I wrote that line I realize that I can actually see those 3 conditions. I see periods of no activity for long periods, short periods in the data.