Researchers use many strategies to evaluate samples, including observation, taking physical measurements, research, and collecting information from groups and individuals. These strategies take various forms depending on the type of sample being evaluated.
Many sample evaluations begin with observation. For a sample of bacteria, this could mean noticing the color or other physical characteristics. Researchers studying a sample of human populations may observe behavioral tendencies or similarities in dress. Observation often helps a scientist form a hypothesis that he can later test with empirical data.
The next step is collecting physical measurements. Size, mass and location all fall into this category. When evaluating samples of soil, a scientist might measure moisture levels and amounts of certain minerals. Human population studies measure things like infant mortality rates and disease prevalence.
It's also important to research existing documents and data for more information. If someone has already answered a question, it's a good idea to find out what he had to say. Even if research doesn't provide the exact information that's wanted, it may give data that can help.
Finally, many researchers get information from groups or individuals within the population. This tactic is geared toward studying human populations, and it includes evaluating surveys or other first-person material such as diaries and memoirs.