Forecasting numbers (exponential/polynomial/moving average)

**froggeja** · 03-19-2009, 10:50 AM

I am trying to forecast a number for 4 periods. I have one row of data B3:AU3 and I'm trying to forecast data for AV3:AY3. I've just run a trendline on a chart and the best fit line is a Polynomial Order 6. Can anyone help with the formula that I would use (or Data Analysis function)

?

Thanks enormously!

Jason

**zbor** · 03-19-2009, 11:10 AM

You can "Display equation on the chart"

You will get something like:

y = 0,0169x6 - 0,4998x5 + 5,7369x4 - 31,926x3 + 88,363x2 - 110,66x + 50,889

Just put it in excel table as any other formula, for example:

=0,0169*POWER(A1;6)-0,4998*POWER(A1;5)+ ...etc...

**froggeja** · 03-19-2009, 11:31 AM

Thanks! Hey - bit of a novice here....

Here's the formula:
y = -2E-06x6 + 0.0002x5 - 0.0096x4 + 0.2034x3 - 2.0318x2 + 5.5521x + 257.36

What is the E?

Thanks
Jason

**zbor** · 03-20-2009, 02:48 AM

E is exponent... -2*10^-6=-0,000002

So your formula look like:

=-2*POWER(10;-6)*POWER(A14;6)+0,0002*POWER(A14;5)-0,0096*POWER(A14;3)+0,2034*POWER(A14;3)-2,0318*POWER(A14;2)+5,5521*A14+257,36

Edit: a tip

For very large numbers it's the same as =-2*POWER(10;-6)*POWER(A14;6)
(you can ignore everything else)