Set intercept as 0 for trendline

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Level 1

1 points

Set intercept as 0 for trendline

Ive done a bit of searching and cant find anything to help me. So i apologize if this has already been answered.

How do i force the intercept to be 0 for the trend line of a scatter chart in Numbers 09? In Excel its as simple as a check box, but i cant seem to find this function in Numbers. The rest of my project has been done in Numbers and it would be a pain so have to re-jigger it to work in Excel.

15" Unibody MBP, Mac OS X (10.5.6)

Posted on Mar 5, 2009 9:05 AM

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Answer 1

Badunit

Level 7

30,708 points

Mar 5, 2009 10:55 AM in response to Badunit

And the answer is: You will have to calculate the trendline in your table and plot the data. The LINEST function allows you to force a 0 Y intercept. See the function browser on how to use the LINEST function to get what you need.

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Answer 2

KOENIG Yvan

Level 8

41,819 points

Mar 5, 2009 10:40 AM in response to winstonef

I really don't understand.

A scatter line is defined according to the stored values.
If we change the INTERCEPT value, it's no longer a trendline.

Here is an example.

In D2 the formula is: =INTERCEPT(C,B)
In D3 the formula is: =SLOPE(C,B)

Happily, the values match those used by the chart tool to display the trendline's equation.

How may we imagine to set INTERCEPT to zero ?

I just discover that there is a way to do that with the LINEST() function 😟

Yvan KOENIG (from FRANCE jeudi 5 mars 2009 19:27:20)

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Answer 3

Badunit

Level 7

30,708 points

Mar 5, 2009 10:50 AM in response to KOENIG Yvan

True, it makes no sense to call such a line a "trendline". It is really a best fit of the data with the stipulation of an intercept of 0. And it is a simple checkbox in Excel.

I'll give it some thought.

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Answer 4

winstonef Author

Level 1

1 points

Mar 5, 2009 12:04 PM in response to winstonef

Your right i should have said line of best fit with intercept at 0, but i was obiously understood as my problem is now solved.

Thanks for the help guys!

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