Which two essential features are present in all statistically designed experiments?

• A. Replication and bias
• B. Randomization and control
• C. Randomization and subjectivity
• D. Control and confounding

Answer: (B)

Verified step by step guidance

1. Understand that a statistically designed experiment aims to produce reliable and valid results by minimizing errors and biases.
2. Identify the key features that help achieve this goal: 'Randomization' and 'Control' are fundamental because they help ensure that the treatment effects are not confounded by other variables.
3. Randomization refers to the process of randomly assigning subjects or experimental units to different treatment groups, which helps eliminate selection bias and balances unknown factors across groups.
4. Control involves keeping all other variables constant or accounting for them so that the effect of the treatment can be isolated and accurately measured.
5. Recognize that while replication and avoiding confounding are important concepts, the two essential features present in all statistically designed experiments are specifically 'Randomization' and 'Control'.