| T O P I C R E V I E W |
| JohnT |
Posted - 04/07/2004 : 01:28:37 AM
Hi.
I did a linear fit and it calculated the upper and lower 95% confidence interval limits of the line. I open the linear fit box and enter a Y value. It calculates the X value and I need the 95% confidence value for that specific point. What do I do to get the info for that? |
| 1 L A T E S T R E P L I E S (Newest First) |
| Mike |
Posted - 04/07/2004 : 10:06:07 AM
Hi John,
I am assuming that you performed your linear fit using the linear fit tool, and that when you did so, you had the Confidence Bands check box selected. Then you used the FindX/FindY feature to find a particular X value for which you would like to calculate the Y value of the upper and lower 95% CI. To do this:
1. Open the Project Explorer window (ALT+1).
2. Find the hidden worksheet LinearFitn(it will be grayed out) and double-click on it to open it.
What you see are the X and Y values of your linear fit, along with the Y values of the UCL and LCL. You will use these data to find the interpolated UCL and LCL values at your X value.
3. Open the Script window (ALT+3)and type:
LinearFitn_ucl(your X value) <ENTER>
This returns a UCL Y value for your X value (be sure to substitute the number that follows "LinearFit" in the worksheet name for n). This command says, in effect, "using interpolation and the calculated data set LinearFitn_ucl, calculate a Y value at your X value."
4. Enter the following into the Script Window:
LinearFitn_lcl(your X value) <ENTER>
This returns a LCL Y value for your X value.
FYI, there is a brief tutorial (Help:Tutorials) on using the Script Window to perform calculations (Origin 7 = Tutorial 9; Origin 7.5 = Tutorial 13).
I hope this helps.
Mike
OriginLab
Edited by - Mike on 04/07/2004 10:28:39 AM
Edited by - Mike on 04/07/2004 11:05:02 AM |
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