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Numerical Approximation

galc81

New member
Mar 14, 2013
1
Hi all,
i have a problem to solve that i want maybe to solve with matlab o excel.
I have a numerical samples and with linear approsimation i have a function, but now i want to use less samples for example only 20 and i want to find the best set of samples to approsimate in the best way the function.
thanks a lot
 

Ackbach

Indicium Physicus
Staff member
Jan 26, 2012
4,191
Hi all,
i have a problem to solve that i want maybe to solve with matlab o excel.
I have a numerical samples and with linear approsimation i have a function, but now i want to use less samples for example only 20 and i want to find the best set of samples to approsimate in the best way the function.
thanks a lot
Well, I suppose there are a number of ways you could choose your samples: break up the independent variable domain into 19 equal-width chunks, and use the endpoints (20 of them) as your samples. You might or might not have data for those points, naturally, so you could choose the ones closest to those that you do have.

The big question in my mind is this: from a statistics perspective, you usually want the largest sample size you can get, because your predictions and descriptive power are always greater when you have a larger sample size. So why do you want to reduce the size of your sample? Excel, for example, can crunch through quite a large sample size.