Mason asks his friends at school to do his questionnaire. This may not be a good sample to use.

The sample is ... (what?)

They might be the same ... (what?)

The sample is his friends. They might be the same group of interests. The sample needs to be random. Even if he went around and grabbed random people he may not have known at his school, it still wouldn't be random bc they could all be bias towards a local sports team or have different interests than someone from somewhere else