The best sampling method for the scenario described is Systematic Sampling.

Explanation:

In Systematic Sampling, you select every k-th individual from a list, where k is a fixed number. In this case, the teacher decided to check every third student who shows up to class, which matches the characteristics of systematic sampling.

Why Systematic Sampling is Best:

• The teacher wants to avoid bias, so selecting every third student gives a random starting point and ensures a consistent and non-biased approach for the sample.
• By using a fixed interval (every third student), the teacher can manage time effectively without checking everyone.
• This method is also simple and practical, especially when the total population is large and the teacher doesn’t have enough time to check every student.

Key Steps in Systematic Sampling:

1. Select a random starting point (for example, randomly choose a student from the first few students).
2. Choose every k-th student (in this case, every 3rd student after the first one).

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Would you like further details on how systematic sampling works, or other methods of sampling? Let me know if you need anything clarified!

Here are some additional questions that may interest you:

1. What is the difference between systematic sampling and simple random sampling?
2. How does the sample size impact the reliability of the results in sampling methods?
3. Can systematic sampling introduce bias in certain situations?
4. What is stratified sampling, and when might it be more appropriate than systematic sampling?
5. How do you calculate the sample size for a survey to ensure accurate results?

Tip:

Systematic sampling works best when there’s no inherent order or pattern in the list. If students are seated in a specific order (e.g., alphabetically by last name), it could unintentionally introduce bias.