What is the primary function of a questionnaire in research?

A questionnaire primarily serves the function of collecting standardized information for data analysis. This tool is designed to gather quantitative data systematically, allowing researchers to compile responses from a large sample size. The format of a questionnaire typically consists of closed-ended questions, which yield responses that are easy to quantify and analyze statistically. This standardization ensures consistency in the data collected, facilitating comparisons across different respondents and groups.

By employing a questionnaire, researchers can effectively quantify variables of interest, test hypotheses, and derive generalizable findings that are representative of the entire population being studied. This method is particularly useful in surveys where broad trends and patterns are sought, enabling researchers to draw conclusions based on the aggregated data.

The other choices focus on approaches that are generally more qualitative or detailed in nature, such as interviews and focus groups, which diverge from the standardized data collection that questionnaires provide.