2.1.982 Part 1 Section, LINEST

a.   The standard states that x and y are sample means.

Office treats x and y as the sample values, and x-bar and y-bar as the sample means of known-xs and known-ys, respectively.

b.   The standard does not place any restrictions on dimensions of known-ys or known-xs.

In Office, if known-ys and known-xs are both specified but don't match in size (or number of variables for the multivariate case), #REF! is returned.

c.   The standard describes statistic seb as the standard error value for the constant b.

In Office, if b is forced to be zero (const-flag=FALSE), then it has no standard error and #N/A is returned.

d.   The standard does not mention collinearity cases for this function.

In Excel, vectors in known-xs that are collinear (have no additional predictive value because they can be expressed as sum of multiples of existing vectors) are omitted from the regression calculations. The vectors are given a coefficient of 0 and a standard error of 0 (m = 0; se=0).  If vectors are omitted, df is affected because df depends on the number of values used for predictive purposes.

e.   The standard states the syntax is: LINEST  (  known-ys  [  ,  [  known-xs  ]  [  ,  [  const-flag  ] [  ,  stats-flag  ] ]  ).

Office uses the following syntax: LINEST  (  known-ys  [  ,  [  known-xs  ] [  ,  [  const-flag  ] [  , [  stats-flag  ] ] ] ] ).