forum.alglib.net

hellp everyone,I have data below

x , y
2001,75330
2002,75636
2003,71422
2004,70952
2005,75398
2007,78281
2008,79524
2009,72624

I want to fitting the Y ,when x equal 2006.
which method can be chosen.

With such small amount of data and such large non-monotonic variations it is better to use something simple. Complex methods won't work.

I think, it is better to calculate Y(2006) as 0.5*(Y(2005)+Y(2007)). You may think that it is too simple, but the problem is that there is no magic formula which can predict sudden changes like ones which happened in 2003 (75000 to 71000) and 2005 (70000 to 75000).