Question

Method of sampling which involves dividing the population into sub-populations that may differ in important ways

• A. Simple random sampling
• B. Systematic sampling
• C. Stratified sampling
• D. Cluster sampling

Hint:

Think of "Strata" as "Layers." If your fish population has different sizes (small, medium, large), Stratified sampling ensures you don't end up with a sample that has only small fish by chance.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question identifies a specific sampling technique used in statistics and fisheries surveys where a heterogeneous population is segmented into more homogeneous sub-groups.

Step 2: Detailed Explanation:

• Stratified Sampling: This technique involves dividing the entire population into non-overlapping sub-groups called "strata" (singular: stratum). These strata are formed based on shared characteristics (e.g., age, depth, gear type in fisheries).

• Process: After the population is divided, a random sample is taken from each stratum. This ensures that every sub-population is adequately represented in the final sample.

• Advantages: It reduces sampling error and provides more precise estimates than simple random sampling when there is high variation between the sub-groups but low variation within each sub-group.

• Other Options:
- Simple Random Sampling: Every individual has an equal chance of being selected from the whole population.
- Systematic Sampling: Selection is done at regular intervals (e.g., every $k$-th item).
- Cluster Sampling: The population is divided into clusters (like villages), and entire clusters are randomly selected.

Step 3: Final Answer:
The method described is Stratified sampling.