Excel 2007 : Spline or Interpolate function for 2007

I need to use the cubic spline function in 2007? Can I or do I have any other options to fit a polynomial function to estimate or predict an x value on the curve?

Thanks!

I have numerous Y values that occur in time so I can assign the time x values and the y values are below:

X Y
1 45
2 50
3 56
4 62
5 59
6 53
7 58
8 64


So I need to normalize the data to 10 points. So I need the values on that curve at the x-values of..

X
1
1.7
2.5
3.3
4.1
4.8
5.6
6.4
7.2
8

In 2003 I used the spline function. My datasets are going to have between 38 and 47 data points and they must all have 100. Since 2003 will only let me have 7 nested if statements where the value if true is a splined number, I have multiple sheets where the dataset (100 points) might appear. With the 64 nested IF statements in 2007 I can simplify my data interpolation worksheets to just one...not 5 sheets. Does this help?

Free, download now

XlXtrFun.xll is a collection of functions which extends the capabilities of Microsoft Excel; developed primarily to facilitate, interpolation of 2-dimensional and 3-dimensional data, and simplify 2-variable curve fitting. XlXtrFun has been used for years by engineering and research and development personnel on every continent who need to interpolate, extrapolate, and curve fit data rapidly, reliably, and with a virtually non-existent learning curve.
If you work with real-life data and want to interpolate, extrapolate, or curve fit, then you will find these functions very useful.

The website....
http://www.ozgrid.com/Excel/excel-in...-curve-fit.htm

The function reads:

=Spline(Array of x's, Array of y's, given x, extrapolate?)

I FIXED IT!!!!


Actually I never tried to import the addin for the 2003 version because I figured since 2007 puts an "x" on the end of file names it would not work..However, I tried changing all the files by putting an X on the end and tried to import the addin. It did not recognize the files but did recognize the 2003 files...I tried importing those and it actually worked. So all the interpolation and curve fitting functions work in 2007 as well. Thank you for your help and time considering my issue! Have a great day.

Hi,

I use the same functions (xlstrfun), and have recently migrated from excel 2000 to excel 2007.

I go to excel options, manage add-ins, browse,

Then I browse to the copy of xlstrfun.xll on my PC and select it.

However the add-in does not appear in the list.

Am I missing some action?

How exactly did you "import" the add-in.

Thanks

Alan.