A Level Sociology OCR Practice Exam 2025 - Free Practice Questions and Study Guide

In a research study, a control group serves as a baseline to compare the effects of the experimental treatment or intervention. The control group ideally shares similar characteristics to the experimental group but does not receive the treatment, allowing researchers to determine the intervention's effectiveness.

In this case, selecting another year 3 class as the control group is appropriate because it maintains a similar age and developmental stage as the experimental group. This allows for direct comparison regarding any changes that occur due to the specific intervention being applied. By using another year 3 class, researchers can effectively measure the impact of their study with minimal external variations that could skew the results.

The other options are less suitable as control groups due to differences in age and academic level, which could introduce variables not related to the treatment being tested. Using a year 4 class or older students would likely yield different results due to their advanced age and developmental stage, making it difficult to ascertain the direct effects of the intervention on year 3 students. Similarly, another school may have different teaching styles, curricula, and student demographics, all of which could influence the study's outcomes unrelated to the specific treatment being examined.