bug with LINEST and array formula processing?

[carl]

There appears to be a bug in Excel2004 for MacOSX, 11.3.5 (at least).
Here's an example of 2nd order polynomial fit. If I use the format
linest(yarray,xarray^{1,2},1,1)
the results are garbage. If I create two columns, one with x values
and the next with x^2 values, then
linest(yarray, x:x2,1,1) works fine (assuming I've named the two
columns "x" and "x2" ) .
The exact same spreadsheet seemed to produce the correct result using
the first format when run under ExcelX for MacOSX (the older version
of Office). So, there seems to be a problem under Excel2004 in
expanding that power-array part of the formula.

For reference, I used formulas presented in
http://www.eng-tips.com/viewthread.cfm?qid=184726&page=1

I downloaded a sample of TREND using array formulas from
mikemiddleton.com and those appeared to work fine.
http://www.mikemiddleton.com/QuadraticTrendSeasonalForecast.xls

thanks for any help.

Carl

 

[JE McGimpsey]

There appears to be a bug in Excel2004 for MacOSX, 11.3.5 (at least).
Here's an example of 2nd order polynomial fit. If I use the format
linest(yarray,xarray^{1,2},1,1) the results are garbage. If I create
two columns, one with x values and the next with x^2 values, then
linest(yarray, x:x2,1,1) works fine (assuming I've named the two
columns "x" and "x2" ) .

Yes, this is a bug that's been reported before. One workaround:

=LINEST(TRANSPOSE(y_range),TRANSPOSE(x_range)^{1;2},TRUE,TRUE)

The problem appears to be the way that xarray^{1,2} is returned to the
function.

Please report it again to MacBU (via XL's Help/Send Feedback). It may
not be too late to get it fixed in XL08.