One-Way Analysis of Variance for Independent or Correlated Samples
The logic and computational details of the one-way
ANOVA
for independent and correlated samples are described
in Chapters 13, 14, and 15 of Concepts
and Applications.
Procedure:
Initial
Setup:_{T}
Enter the number of samples in your analysis (2, 3, 4, or 5) into the
designated text field, then click the «Setup» button for either
Independent Samples or Correlated Samples to indicate which version of the
one-way ANOVA you wish to perform._{T}
Entering
Data Directly into the Text Fields:_{T}
After clicking the cursor into the scrollable text area for Sample 1,
enter the values for that sample in sequence, pressing the carriage return
key after each entry except the last. (On a Macintosh platform, the
carriage return key is labeled 'Return'; on a Windows platform it is
labeled 'Enter.') Perform the same procedure for the other samples in your
analysis._{T}
Importing
Data via Copy & Paste:_{T}
Within the spreadsheet application or other source of your data, select
and copy the column of data for sample 1. Then return to your web
browser, click the cursor into the text area for sample 1 and perform
the 'Paste' operation from the 'Edit' menu. Perform the same procedure for
the other samples in your analysis._{T}
Data Check:_{T}
For each sample, make sure that the final entry is not followed by
a carriage return. (A carriage return after the final entry in a
sample will be interpreted as an extra data entry whose value is zero. Importing
data via the copy and paste procedure will almost always produce an extra
carriage return at the end of a column.) After all values for a sample
have been entered, click the cursor immediately to the right of the final
entry in the list, then press the down-arrow key.
If an extra line is present, the cursor will move downward. Extra lines
can be removed by pressing the down arrow key until the cursor no longer
moves, and then pressing the 'Backspace' key (on a Mac platform, 'delete')
until the cursor stands immediately to the right of the final entry._{T}
If you are performing a correlated-samples analysis, also make sure
that the values for each sample are entered in the appropriate sequence. Note
that a correlated-samples analysis presupposes equal numbers of
observations for each sample in the analysis._{T}
When all sample
values have been entered, click the button labeled «Calculate.» For independent samples the default analysis is a
standard weighted- means analysis. If you wish to perform an unweighted- means analysis, click the «Unweighted» button before calculating.
Note that when the number of samples is k=2, the analysis of
variance (standard weighted- means analysis) is equivalent to a
non-directional t-test with F=t^{2}.
Setup
_{Q}
Click this button only if you wish to perform
an unweighted-means analysis. Advice: do
not perform an unweighted-means analysis
unless you have a clear reason for doing so.
Click this button to return to a standard
weighted-means analysis
Ss/Bl = Subjects
or Blocks depending on the design. Applicable only to correlated-samples ANOVA.
Tukey HSD Test
M1 = mean of Sample 1
M2 = mean of Sample 2
and so forth.
HSD = the absolute [unsigned]
difference between any two
sample means required for
significance at the designated
level. HSD[.05]
forthe .05 level;
HSD[.01] forthe .01 level.