b1:=INDEX(LINEST(y, x^{1,2}), 1, 2) a:=INDEX(LINEST(y, x^{1,2}), 1, 3) Cubic (3rd order) polynomial trendline Equation: y = b3x3+ b2x2+ b1x + a b3:=INDEX(LINEST(y, x^{1,2,3}), 1) b2:=INDEX(LINEST(y, x^{1,2,3}), 1, 2) b1:=INDEX(LINEST(y, x^{1...
y values, my aim is to come up with a formula which I can use to input an x value to give me the expected y value. When I plot my data on a scatter chart, using a 3rd order polynomial trend line I get an r-squared value of 0.8402. When I use LINEST to get an r-squared.....
Hi Charles, would you be able to give guidance on a method within excel of applying ± 95% confidence limits to a 3rd order polynomial. The limits would then be used to control a process. Thank you in advance for your reply, Reply Charles November 24, 2015 at 1:21 pm Paul, For whic...
You can use LINEST to compute the coefficients in the worksheet. See Bernard Liengme’s tutorial:Polynomial regression: How can I fit my X, Y data to a polynomial using LINEST?. That said, you shouldn’t just use R² blindly to decide which fit is best. Beyond order 2, a polynomial...
=LINEST(B1:B7,A1:A7^{1,2,3},TRUE,FALSE) in a10 using the key combination Ctrl-Shift-Enter. The order-3 best-fit polynomial coefficients are in A1010 If you want a fifth order polynomial =LINEST(B1:B7,A1:A7^{1,2,3,4,5},TRUE,FALSE) substituting A10:F10 for A10:d10 Upvote 0 ...