Question

Which of the following design(s) is/are advocated when experimental units are homogeneous?

• A. CRD only
• B. RCBD only
• C. Either CRD or RCBD
• D. Neither CRD nor RCBD

Hint:

CRD is highly flexible and simple, but its validity depends strictly on the complete homogeneity of the experimental units (e.g., in laboratory or greenhouse experiments).

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
The choice of experimental design depends entirely on the nature and variability of the available experimental units.

Step 2: Detailed Explanation:
Let us compare the applicability of the basic experimental designs:
- Completely Randomized Design (CRD): This design is used when the experimental units are entirely homogeneous. Since there are no external sources of variation among the units, treatments can be assigned completely at random.
- Randomized Complete Block Design (RCBD): This design is advocated when the experimental units are heterogeneous in one direction, requiring them to be grouped into homogeneous blocks.
- Latin Square Design (LSD): Used when there are two crossed sources of heterogeneity (rows and columns).
Therefore, when the experimental units are homogeneous, CRD only is advocated.

Step 3: Final Answer
The correct option is (A).