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CHAPTER IV

Test for Mean Comparison

Learning Objectives:

At the end of the lesson you should be able to

1. Explain the nature and purpose for test of mean comparisons
2. List down and discuss the different tests used in comparing treatment
means.
3. Solve and analyze results of a given study by applying

TOPICS:

 Importance of Comparing Treatment means
 Methods of Testing the Level of Significance
1. LSD Test –- Least Significant Test
2. Scheffe’s Test
3. DMRT Test – - Duncans Multiple Range Test
4. SNK – - Student -Newman Keull’s Test
5. HSD Test - - Honestly Significant Difference test

 After subjecting the result of study to statistical analysis
through the ANOVA and the result of the study is Significant, it
means that the treatment means are significantly different but it
does not pinpoint the specific pair of treatments that are
significantly different from each other.
 A significant F test simply means that at least a pair of
treatment means are significantly different from each other.
 The next step involves comparing the means
o by determining their differences and
o testing whether the differences are significant with the
help of the critical difference.

WHY IS THERE A NEED TO COMPARE TREATMENT MEANS?

Example :
 Consider a study on eggplant applied with 100% organic fertilizer and
the other treatments are mixed with commercial inorganic fertilizer at
varying rates .
 Possible questions that would be asked and the specific mean
comparisons that could answer the questions may be :
- Are the treatments with commercial organic fertilizer better
than pure organic fertilizer/ is bio organic fertilizer better
than those mixed with commercial organic fertilizer? …..So
we have to compare the pure bio organic treatments with
those mixed with commercial organic fertilizer.