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Welcome to Epi Info 7 training.
In this video you will learn how to use the Means gadget with ANOVA or
analysis of variance
in the Visual Dashboard.
I'm in the Visual Dashboard and I've already loaded the E. Coli project
that's included in Epi Info 7.
We want to determine if there is a significant difference in ages between
females and males in this dataset.
I'll navigate to the Means gadget,
in the Means of drop-down i'll choose age
and click Run.
This gives us the mean age for the whole dataset,
but we want to know the difference in ages between females and males.
To do that
we'll reopen the configuration panel
and go to Advanced Options,
and in the Cross Tabulate by,
I'll scroll down to Sex
and click Run.
The result has several tables.
The top table shows us the values for the two groups.
Then we have the T-test which only applies when the cross tab has only
two levels. So we'll close the T-test
and we'll look at the ANOVA.
The first section shows the F-statistic
and then underneath that table is the P-value for the statistic.
In this example the P-value is .34 which is not what we would
consider significant.
So we can say there's not a significant difference in ages between female and
male.
The next table contains a statistic
that compares the variances between the two groups.
That P-value is .58.
So that also says that age variance is not significantly different between the
sexes.
If the variance was different,
we would need to use the table at the bottom and its P-valuel to compare the
means.
So let's go back to the T-test
As I said before,
because the variable Sex has two levels, female and male,
the gadget also produces this T-test.
The T-test output contains a difference between the means of the two groups
along with a confidence interval,
a T-statistic,
and a P-value for the statistic.
It does that twice under the assumption of equal variance and again for unequal
variance.
In this example all those statistics agree with the ANOVA that the
difference in the ages of the two groups is not statistically different.
You've just been shown how to perform a means analysis with ANOVA in the Visual
Dashboard.
Thanks for watching
and look for more user support videos coming soon.