The correct answer is D. Sampling.
Sampling is a data collection method that involves selecting a subset of individuals or elements from a larger population for study. This is done in order to save time and money, as it is often not feasible to study the entire population. The sample should be representative of the population, meaning that it should have the same characteristics as the population as a whole. This can be done by using random sampling, which ensures that each individual in the population has an equal chance of being selected.
Observational studies are a type of research that involves observing people or events without interfering with them. This type of study is often used to study human behavior, as it can be difficult to control all of the variables that might affect the results. Surveys are a type of research that involves asking people questions about their beliefs, attitudes, or behaviors. Surveys can be conducted in person, over the phone, or online. Experiments are a type of research that involves manipulating one variable and observing the effect that it has on another variable. Experiments are often used to test the effectiveness of new treatments or interventions.
Here are some examples of sampling:
- A polling company might select a random sample of voters to survey about their opinions on a particular issue.
- A market research company might select a random sample of consumers to test a new product.
- A medical researcher might select a random sample of patients to participate in a clinical trial.
Here are some examples of observational studies:
- A sociologist might observe people’s behavior in a public place.
- A psychologist might observe children playing in a playground.
- An anthropologist might observe a tribe of people in their natural habitat.
Here are some examples of surveys:
- A government agency might conduct a survey to find out how many people are unemployed.
- A business might conduct a survey to find out what customers think of their products or services.
- A non-profit organization might conduct a survey to find out how many people need their services.
Here are some examples of experiments:
- A pharmaceutical company might conduct an experiment to test the effectiveness of a new drug.
- A farmer might conduct an experiment to test the effectiveness of a new fertilizer.
- An engineer might conduct an experiment to test the strength of a new material.