Home |
Search |
Today's Posts |
#1
|
|||
|
|||
Linest - Why did they do that?
I am having difficulty with the order of the coefficients outputed by linest
when doing a multivariable regression. My problem is that the order is reversed from the input x variables. While for displaying the coefficients I do not have a problem, the problem is that my sheet is setup so that the column order is x1,x2,x3,x4... and I would like to use mmult(inputs,transpose(output coefficient)) or Sum(inputs*ouput coefficients) ) to fill in dataspace in other operations. Any suggestions on a way reverse the order so that I can use it with matrix operations without creating new columns in reverse order (involves reverse thinking on my part). Thanks in advance cseeton |
#2
|
|||
|
|||
I don't know that my solution could even be called good, but I used a
modified identiy matrix 0 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 0 to flip a column of data to that it would work with the index() function. I simply used mmult to multiply the column with the matrix and I had the data in the form I needed it. It will also work if the data is in a row. Unfortunately, this was the only work around I could find in Excel. "cseeton" wrote in message ... I am having difficulty with the order of the coefficients outputed by linest when doing a multivariable regression. My problem is that the order is reversed from the input x variables. While for displaying the coefficients I do not have a problem, the problem is that my sheet is setup so that the column order is x1,x2,x3,x4... and I would like to use mmult(inputs,transpose(output coefficient)) or Sum(inputs*ouput coefficients) ) to fill in dataspace in other operations. Any suggestions on a way reverse the order so that I can use it with matrix operations without creating new columns in reverse order (involves reverse thinking on my part). Thanks in advance cseeton |
#3
|
|||
|
|||
You could use the INDEX() function to reverse the coefficients, as in
=INDEX(LINEST(B1:B6,A1:A6),1,{2,1}) My guess as to why LINEST works this way, is that if you are doing model selection (such as testing whether a quadratic term is a significant improvement over a linear fit), you can do the test without displaying all the columns of LINEST output. Yes, that's pretty weak, and I would have preseverd the order of input columns, but I didn't write it ... Jerry cseeton wrote: I am having difficulty with the order of the coefficients outputed by linest when doing a multivariable regression. My problem is that the order is reversed from the input x variables. While for displaying the coefficients I do not have a problem, the problem is that my sheet is setup so that the column order is x1,x2,x3,x4... and I would like to use mmult(inputs,transpose(output coefficient)) or Sum(inputs*ouput coefficients) ) to fill in dataspace in other operations. Any suggestions on a way reverse the order so that I can use it with matrix operations without creating new columns in reverse order (involves reverse thinking on my part). Thanks in advance cseeton |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
How do I reverse the linest coefficients? | Excel Worksheet Functions | |||
LINEST maximum number of predictor variables | Excel Worksheet Functions | |||
Excluding 0s and blanks from a LINEST function | Excel Worksheet Functions | |||
how can i fill a table with values from repeated regressions | Excel Worksheet Functions | |||
Trend Lines (or Linest?) | Excel Worksheet Functions |