Which of the following are the must important parts of designing a fair test'?

1. Control variables: Ensuring that all variables, except for the independent variable being tested, are kept constant to eliminate any potential confounding factors.

2. Randomization: Randomly assigning participants to different groups or conditions to minimize bias and ensure that the results are representative of the population.

3. Replication: Conducting the experiment multiple times to ensure that the results are consistent and reliable.

4. Sample size: Ensuring that the sample size is large enough to provide statistically significant results and reduce the likelihood of random variation influencing the outcome.

5. Clear hypothesis: Clearly defining the research question and hypothesis being tested to guide the design of the experiment and interpretation of the results.

- Identifying the variables
- Controlling the variables
- Random assignment to groups
- Replication
- Blinding