Jerry,
In XL2007 with all three I get
1 2.22045E-16
0.353553 0.75
0.8 0.5
8 2

And trendline on the last dataset gives the same slope and r², but intercept
zero

Please remind me: If I have a formula such as one of yours, how do I copy
and paste and make the array formula. Right now I must select all the cells
and then type it. I know there is a way but I have forgotten.
best wishes
--
Bernard V Liengme
Microsoft Excel MVP
http://people.stfx.ca/bliengme
remove caps from email

"Jerry W. Lewis" wrote in message
...
Help for LINEST states that

The array known_x's can include one or more sets of variables. If only one
variable is used, known_y's and known_x's can be ranges of any shape, as
long
as they have equal dimensions. If more than one variable is used,
known_y's
must be a vector (that is, a range with a height of one row or a width of
one
column).

In particular,
=LINEST({1,1.5;2.5,3},{1,2;2,3},,TRUE)
should be equivalent to either
=LINEST({1;1.5;2.5;3},{1;2;2;3},,TRUE)
or
=LINEST({1,1.5,2.5,3},{1,2,2,3},,TRUE)

Prior to 2003, they were equivalent (as documented), but in Excel 2003,
not
even the degrees of freedom for =LINEST({1,1.5;2.5,3},{1,2;2,3},,TRUE)
match
the documented behavior.

What happens in 2007?

Jerry