Representativeness & Generalisablity 

• Representativeness is how well a chosen sample reflects the broader population. In research, a sample is selected from the target population. For representativeness, this sample must be a diverse cross-section of the target population, accurately reflecting its diversity. If the study's respondents lack diversity, the representativeness is considered low.
• Generalizability refers to how findings can be applied beyond the target population, which is important as the aim of research is to understand the behaviour of people in general. More people involved and more sophisticated sample methods used means a more generalisable study. It is unlikely to be generalizable unless it's representative of the group. A study that isn't generalizable has limited use.
• Positivists carry out large scale, quantitative research with large samples which are more likely to be a diverse cross section of the target population- their key focus is to gather data that provides a bird's eye view of society. However, large samples may sometimes under-represent some groups, so are not always best.
• Interpretivists focus on small scale samples, usually focusing on one individual or a small group of individuals. This ensures they meet the specific criteria of the target population, giving us an excellent view of hard to reach groups. However positivists argue small samples exclude some voices due to the unsophisticated approach to sampling and that they are less likely to be diverse and reflect a variety of backgrounds.