Final answer:
An experiment does not require that every step of the scientific method be conducted in a fixed order for results to be valid, but it should include a control group, random assignment, and often, blind testing to ensure reliability and reduce bias.
Step-by-step explanation:
One rule that does not need to be followed for experimental results to be valid is performing every step in the scientific method in the exact order described in a specific chapter or sequence. While the scientific method provides a rigorous framework for conducting experiments, it is not a strict sequence of steps that must be followed inflexibly. Scientific investigation often requires adaptability and critical thinking, especially when experiments yield unexpected results or when refining hypotheses and experimental designs.
Key components for a properly conducted experiment include having a control group, using random assignment to eliminate lurking variables, ensuring that any treatments given to the experimental group are the only differences between groups, which could explain the observed differences, and conducting blind experiments to reduce bias. Additionally, repetition of experiments is important to verify results. However, it is not necessary for all experiments to rigidly stick to a prescribed order in conducting these aspects as they can be adapted as science progresses.