Give a reason why Tom should also find opinions of people where HS2 will not have a station.

To test his hypothesis about what "most people" think, Tom needs a sample that is representative of the entire population, not just those who live near or use the new HS2 stations. People in areas not served by HS2 are still affected by the project through its national cost (funded by taxes) and widespread environmental impact. Their opinions are crucial for a balanced and valid conclusion. They may be more likely to be against it as they perceive fewer direct benefits, so excluding them would likely bias the results in favour of HS2.