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EMS = Error Mean Square

r = Replication

O. Use Duncan’s Multiple Range Test if we compare all the treatments
with each other.

1. Compute the critical value for the test.
Rp = (rp) (s-d) for p = 2, 3, 4, 5

2

where:

Rp = critical values for DMRT at corresponding p

p = distance in rank between treatment mean
compared as p = 2,3,…n

rp = tabular values for significant studentized range
at corresponding p

s-d = standard error of the mean difference

______
s-d = √ 2 EMS

r
2. Look for the value of rp at p =2,3,…n. using the error do at 5%
or 1% level of significance.
3. Solve for the rp for various ranges of means using the formula
in step 1.
4. Rank the means for comparison from highest to lowest.
5. Compare the means using the following procedures.
a. Subtract the highest Rp from the highest mean, means lower
than this value are declared significantly different from the
highest mean while higher to the difference is declared to be
not significantly different from the highest mean.
b. Subtract the second highest Rp from to the second highest
mean. Then do the same procedure up to the first to the last
lowest mean.