credited to Deepak

1. Presentation on the Topic of
Confounding -2.
Submitted to: Dr. Manwinder Kaur
Submitted by: Deepak
Class: M.Sc. Agronomy
Part -1 (Sem. 2nd)
Roll no: 10006

2. What is Confounding?
When only the portions of treatment
combinations are allotted to block within
replication, the comparison between blocks
in a replication represents some treatment
comparison, either a main effect or an
interaction. In such cases it is not possible
to distinguish treatment comparison from
block comparisons. Such a mix up is termed
as confounding.

3. Types of Confounding
1.Complete confounding
2.Partial confounding

4. Partial Confounding
If a treatment effect is confounded in
some replications and unconfounded in
order replication the system is known
as partial confounding.

5. Example: The following 2*3 factorial
experiment in blocks of 4 plots, involving three
fertilizer N,P,K each at two level.
Replicat
ion I
Replicat
ion I
Replicat
ion II
Replicat
ion II
Replicat
ion III
Replicat
ion III
Block 1 Block 2 Block 3 Block 4 Block 5 Block 6
np P (1) Np Pk N
101 88 125 115 75 53
Npk N Npk K Nk Npk
111 90 95 95 100 76
(1) Pk Nk Pk (1) P
75 115 80 90 55 65
K Nk P N Np K
55 75 100 80 92 82

6. Step 1: Grand total = 0
Step 2: Block S.S and Total S.S
S.S due to blocks = B*B/4-C.F = 2506
Total S.S = Observed* Observed – C.F. =
8658
Step 3:
Treatment
combination
Total yield Factorial
effect
Sum Squares
(1) 255 G= 0
N 223 (N)=48 96= S*S(n)
P 253 (P)=158 1040.17=S*S(
p)
Np 308 (NP)=66
K 232 (K)=10 4.17=S*S(k)
Nk 255 (NK)=2
Pk 280 (PK)=-8 2.67=S*S(pk)
npk 282 (NPK)=-108

7. 1. S.S. due to NP = 1/16(NP*NP) = 529
2. S.S. due to NK = 1/16(NK*NK) = 20.25
3. S.S. due to NPK = 1/16 (NPK*NPK) =
240.25
4. Treatment S.S. = 1932.7501

8. S.O.V D.F. S.S. MS “F”
Ratio
Blocks 5 2506 501 1.31
Treatme
nts
7 1932.75 276.107 -
N 1 96.00 96.00 -
P 1 1040.16 1040.16 2.71
NP 1 529.00 529.00 1.3
K 1 4.41 4.41 -
NK 1 20.25 20.25 -
PK 1 2.66 2.66 -
NPK 1 240.25 240.25 -
Error 11 4219.24 383.57
Total 23 8658

9. References
1. Rangaswamy R . A textbook of
Agriculture Statistics.
2. Vijay Katyal and Gangwar B. Statistical
methods for Agricultural field
experiment.
3. PK Sahu. Agriculture and Applied
Statistics II.