This screen performs a one-way ANOVA from summary data -- that is, from the counts, means, standard deviations (or standard errors) for each group. This can be useful if you don't have the individual numbers for the members of each group, but only the summarized data. This might happen, for example, if you're analyzing data that has been summarized in a book or published article.
A one-way ANOVA can be thought of as an extension of the unpaired Student t-test to more than two groups. Or, you can think of the Student t -test as a special case of the ANOVA for only two groups (or "levels" in ANOVA terminology). A two-level ANOVA is algebraically equivalent to a t-test, and produces exactly the same p values. This page can handle up to 8 groups.
To use this page you must know how many observations are in each group,
and you must know the average (arithmetic mean) and either the
standard deviation (SD) or the standard error of the mean (SEM)
for the observations in each group. Enter them in the table below (leaving
the unused cells blank). Indicate, by the pop-up menu above the last column,
whether you've provided SD's or SEM's. Then click the "Compute" button. The
results will appear in the conventional "ANOVA Table" below. A p-value less
than 0.05 indicates that there is a significant difference somewhere among
the various groups; that is, they do not appear to have all come from the
same population.