One-Way ANOVA

(This page has been taken as is from the next site: http://faculty.vassar.edu/lowry/anova1u.html, copyrights stills to the original author: ©Richard Lowry)

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=t².

Setup
Number of samples in analysis =
_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

Data Entry
Sample 1	Sample 2	Sample 3	Sample 4	Sample 5

Data Summary
	Samples
	1	2	3	4	5	Total
N
-X
-Mean
-X²
Variance
Std.Dev.
Std.Err.

Source

Treatment
[between groups]

Error

Ss/Bl

Graph Maker

Total

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] for the .05 level;
HSD[.01] for the .01 level.

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