Regression curve equation

ib@32 · Newbie Joined: 02 Apr 2005 Posts: 3

Hi
I'm working on a physics expiriment report and I need to get the equation of a regression curve , I know how to do it in Excel (the teacher showed us in the class) but I cant find any way to do it in OO .
can anyone help me with this ?

(forgive me for my English it's not my native language)

AndrewZ · Posted: Sat Apr 02, 2005 1:29 pm Post subject:

You want to do a spreadsheet formula to make a calculation? If so, it may be similar to Excel. How do you do it in Excel?

ib@32 · Newbie Joined: 02 Apr 2005 Posts: 3

No
when we do the expiriment in the lab we get some results which I use to make a graph .
In Excel in the regression curve options you can tell it to put the equation in the graph , for instance if I get this values in the graph :
1 3 (1*1*2+1)
2 9 (2*2*2+1)
3 19 (3*3*2+1)
4 33 (4*4*2+1)
5 51 (5*5*2+1)
and tell Excel to use a power-type regression curve it'll gives me the equation Y=2X^2+1
is there any way to do this thing in OO?

AndrewZ · Posted: Sat Apr 02, 2005 2:26 pm Post subject:

I see. You create a graph from a set of data, and then you want to calculate the regression from the graph. I did that for my physics class a few weeks ago.

1. Make your graph. It must be an XY chart.
2. Click on the chart to select it.
3. Double click on the chart to "enter" it.
4. Double click on a data point to bring up "Data Series" dialog.
5. Under the Statistics tab, there is an area for Regression curves.

You can also find this info in the OOo help under Regression.

joerg04 · Posted: Sat Apr 02, 2005 3:56 pm Post subject:

@aziem, I guess he knows how to do this.

@ib@32, your English is perfect Very Happy

It is not so easy possible with OOo to show the equation like in EXCEL. You must do it by hand.
OOo can give you the parameters for linear and exponential regression.
For power-type look here please (at the part that SergeM wrote):
http://www.oooforum.org/forum/viewtopic.phtml?t=3155&highlight=power+regression
SergeM (Serge Moutou) has done a good job -> http://www.ooomacros.org/user.php#104423
In the help you will find how to calculate R square.
Then you can write your equation in math with your parameters.

ib@32 · Newbie Joined: 02 Apr 2005 Posts: 3

hmm thanks guys , tryed gnumetric and it seems like it cant do this to .
guess I'll have to use M$ excel

Sam_F · General User Joined: 03 Jun 2005 Posts: 5

I'm having this same problem. I found this thread, and got as far as downloading the macro, but now am not sure what to do with the macro. Are there any instructions?

Thanks!

David · Posted: Sat Jul 09, 2005 7:27 pm Post subject:

Science_Guy · Newbie Joined: 10 Nov 2005 Posts: 1

This is a major shortcoming of OOo. What's the point of running a regression if you can't display the equation? The programmers understand that this makes Calc completely useless to scientists and engineers, right?

I was HOPING that Calc would treat graphing as a major feature instead of an afterthought like Excel. Guess not.

RGB · Posted: Fri Nov 11, 2005 1:41 am Post subject:

GDC · Newbie Joined: 09 Jan 2006 Posts: 1

RGB

Excel is the defacto spreadsheet of Science and Engineering, at least in an industrial sense. I agree with Science Guy that the inability to show the equation for a regression line is a major shortcoming of this package.

RGB · Posted: Mon Jan 09, 2006 6:56 am Post subject:

tbonepower07 · Newbie Joined: 18 Jan 2006 Posts: 3

A graphing calculator should be able to do this.
A TI-83 - a very common graphing calculator - has simple ways to find regression curves. They are expensive, but are very common so you should be able to borrow one from somebody, possibly a friend or faculty member.

David · Posted: Wed Jan 18, 2006 5:13 pm Post subject:

doudavisej · Newbie Joined: 25 Sep 2007 Posts: 3

I just saw a presentation on new features in OOo 2.3. One was select regression curve on the chart and the equation appears.