Power Fit - Trendline

[Guest]

Is it possible to link the Power Fit result back to the spreadsheet for
further data analysis?

My chart accurately displays all values however, I need to use these values
for further data analysis.

Thank you.

 

[Bernard Liengme]

Suppose you have a plot of y=2x^3 with the x-values in A1:A12 and y-values
in B1:B12
Select two cells and enter =LINEST(LN(A1:A12),LN(B1:B12)) and use
CTRL+SHIFT+ENTER to complete it
You will get 3 and 0.693147
Suppose the 0.69 value is in E1 then =EXP(E1) gives you the 2
Now you know the parameters of the power curve
This is shown on my website
www.people.stfx/bliengme/ExcelTips/Polynomial.htm but it seems the
university server is dead (again!) today
best wishes

 

[Jon Peltier]

The power law fit gives Y = k X^n. You can transform this into a simple
linear regression model:

log Y = log K + n log X

Put the log of X and Y into two more columns, and use LINEST or simply SLOPE
and INTERCEPT to determine log K and n.

- Jon