I've not seen any particularly helpful responses to this post,
so here's my attempt:
On Thu, 15 Jun 2000 [EMAIL PROTECTED] wrote:
> Hello, I am a 16 year old student and a beginner to statistics.
> I'm lost.
I'll assume you have access to some standard elementary statistics
textbook. If this is not the case, let me know and I'll try translating
any technical language in the sequel into, as you put it, simple English.
> Currently I only have Microsoft Excel 97. And I would like to know the
> differences between the following ANOVA tests (in Excel):
ANOVA = analysis of variance (as I suppose you already know), a very
general technique for testing the null hypothesis that the population
means in several well-defined subgroups are all equal. For further
elaboration see your text.
> ANOVA Single Factor = one-way ANOVA
> ANOVA Two-Factors with replication
> ANOVA Two-Factors without replication
Both of these are variations on two-way ANOVA. I do not have Excel, so
I will guess that "without replication" means that there is only one
observation (or case) in each of the cells (subgroups) of the two-way
design; and "with replication" means that there are more than one
observation per cell. I would further guess that the number of cases per
cell (in the "with replication" program) is required to be the same for
all cells in the two-way design. (This constraint is not a logical
requirement for two-way ANOVA, but it greatly simplifies both the
programming required and the interpretation of results. It is not
required for one-way ANOVA at all, generally.)
> What do all these mean?
Read my replies above with your textbook in hand, open to the
chapters on one-way and two-way ANOVA.
> Where and when should they be applied?
Whenever it is useful to address the question, "Are the means
equal?" for a set of subgroups (or cells, or categories) for which you
have data, and it makes sense to consider the means (averages) of some
variable in each of the subgroups.
> And can anyone please use simple english terms to explain?
> I am only a beginner.
> What is one-way or two-way ANOVA?
If it is not yet clear from the above in conjunction with your text,
perhaps you can identify an example in the text and transcribe it for us
(An example you supply is likely to make more sense to you than a real or
fictitious example one of us might be inclined to use, I suspect.)
> How about for T-Test?
> T-Test: Paired two samples for means
> T-Test: Two-sample assuming equal variances
> T-Test: Two-sample assuming unequal variances
As the old song has it, T is for two [groups], and only two; for more
than two groups, use ANOVA.
"Paired samples" means that each observation in one sample
corresponds to an observation in the other sample, and vice versa:
as though you had taken measures on several persons in one sample, and
the same measures on their identical twins in the other; or the one
sample consists of "before" values and the other of "after" values, for
the same persons. Hence there is a pair of values for each entity of
interest (each pair of twins, or each person, respectively).
"Two samples" would mean two independent samples -- different
persons altogether in each group. Assuming the variancs of the two
groups to be equal (or unequal) I take to be self-explanatory?
> Also, can I use ANOVA instead of T-test when testing null hypothesis?
> Between 2 groups?
Yes. A one-way ANOVA on two groups is entirely equivalent to a t-test
for two independent samples, assuming equal variances.
(The square of the value of t calculated in the t-test is the value of
F calculated in the ANOVA.)
-- 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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