In which type of statistical study is the population influenced by researchers?

• A. Meta-analysis
• B. Survey study
• C. Observational study
• D. Experimental study

Answer: (D)

Verified step by step guidance

1. Understand the key types of statistical studies: observational studies, survey studies, meta-analyses, and experimental studies.
2. Recognize that in an observational study, researchers observe subjects without influencing them, simply recording data as it naturally occurs.
3. Note that a survey study involves collecting data through questionnaires or interviews without manipulating any variables.
4. Know that a meta-analysis combines results from multiple studies to draw broader conclusions but does not involve direct influence on populations.
5. Identify that an experimental study is the type where researchers actively manipulate one or more variables to observe the effect on the population, thus influencing it.