I can't reproduce this. Just a couple of checks - do you have your
X1,X2,X3 in contiguous columns (e.g., =LINEST(D1:D50,A1:C50,TRUE,TRUE))?

Are you selecting at least a 4-column by 5 row area to array-enter the
formula?


In article ,
Mark Schreiber wrote:

Recently had Excel 2003 SP2 loaded onto my PC. When I tried to use LINEST
function, it did not behave correctly. For a simple linear equation, y = mx
+ b, when I filled in "=LINEST(Y-Data, X-Data, True, True)", with X-Data and
Y-Data the ranges containing the single columns of data as appropriate, the
function results were correct. However, when I tried to use it to evaluate
parametric data for two or more X-variables, such as y=ax1 + bx2 + cx3, it
only returns the coefficient for the x3 variable, showing a=0 and b=0. Is
there a bug in the LINEST function in Excel 2003? If not, and there is just
something to do with the Excel load on my PC, is there a way to correct it
without totally reinstalling MS Office?