On Fri, 28 Apr 2000, Arvind Shah wrote:
> I have an UNBALANCED nested (also called hierarchial) design with
> Factor A being fixed and the Factor B (within A) random. So my ANOVA
> has the line entries (for source): A, B(A), Error (or within cell) and
> total. I am looking for the expected mean squares and approaches for
> computing confidence intervals on the mean for different levels of A.
> Any help or reference will be highly appreciated.
When you write "unbalanced", do you mean only that the number of cases
within each cell is not equal in all cells; or do you mean the more
serious problem that the number of levels of Factor B differs between
levels of A?
If the former, perhaps the simplest approach would be an
unweighted means analysis (which really means "equally weighted", not
"UNweighted"!), for which the expected mean squares would be pretty much
what they'd be for a balanced design (especially if the unbalancing is
not really severe). Confidence intervals on the means for different
levels of A might want to vary according to the number of cases in each
level; confidence intervals on the _differences_ between means would be
more difficult.
Alternatively, cast the entire problem into multiple regression
format, using indicator variables of one kind or another to represent the
several levels of A and of B.
-- DFB.
------------------------------------------------------------------------
Donald F. Burrill [EMAIL PROTECTED]
348 Hyde Hall, Plymouth State College, [EMAIL PROTECTED]
MSC #29, Plymouth, NH 03264 603-535-2597
184 Nashua Road, Bedford, NH 03110 603-471-7128
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