You've had a good "flash response" from Jay Warner.
Other short answers embedded in original query below:
On Sat, 3 Feb 2001 [EMAIL PROTECTED] wrote:
> I have two factors A and B and I want to run a DOE to study my
> response. My factor B is at 3 levels; (900, 1450 and 2000) , my factor
> A is at 4 levels 35, 65, 80 and 105.
> First of all is it right to have one factor at 4 levels.
"Right" I don't know about. There's nothing _wrong_ with it.
If it is logically required by the problem, or useful for design reasons
of one sort or another, it is certainly defensible.
> This will require me to have 12 runs for a full factorial, right?
Your arithmetic is correct.
> Also, I want to run the level 35 of factor A only with the level 900
> of factor B. If I remove the combination 35, 1450 and 35, 2000;
> I'll have only 10 runs and the resulting design spce will not be
> orthogonal.
True.
> How do I tackle this problem?
> Is there a different design that you would suggest.
Depends on what you're carrying out this experiment for, and why it makes
sense to omit those two design points. But one way to approach the
problem is to treat the data as a one-way design with 10 levels, and
model the detailed questions you want to ask via assorted contrasts.
Of course, the contrasts will probably not be orthogonal; but having
found out some (preliminary?) things about the situation in this run,
you can then more intelligently design a subsequent run, perhaps with
fewer than 10 combinations, or with a design of the sort Jay suggested.
-- DFB.
----------------------------------------------------------------------
Donald F. Burrill [EMAIL PROTECTED]
348 Hyde Hall, Plymouth State College, [EMAIL PROTECTED]
MSC #29, Plymouth, NH 03264 (603) 535-2597
Department of Mathematics, Boston University [EMAIL PROTECTED]
111 Cummington Street, room 261, Boston, MA 02215 (617) 353-5288
184 Nashua Road, Bedford, NH 03110 (603) 471-7128
=================================================================
Instructions for joining and leaving this list and remarks about
the problem of INAPPROPRIATE MESSAGES are available at
http://jse.stat.ncsu.edu/
=================================================================
