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Research involves a controlled, systematic approach to obtain an answer to a question.1 A number of research types are recognized:
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- Experimental research: involves the manipulation of a variable and then measuring the effects of this manipulation.1 A variable is a measurement of phenomena that can assume more than one value or more than one category (see later).1
- Nonexperimental research: does not manipulate the environment but may describe the relationship between different variables, obtain information about opinions or policies, or describe current practice.1
- Basic research: generally thought of as laboratory-based research in which the researcher has control over nearly all aspects of the environment and subjects.1
- Clinical or applied research: refers to research that seeks to solve practical problems by finding solutions to everyday problems, cure illness, and develop innovative technologies.
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Statistics is a branch of applied mathematics concerned with finding patterns in data and inferring connections between events.2 A number of statistical terms and definitions are outlined in Table 3-1.
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Populations and Samples
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A population consists of all subjects (human or otherwise) that are being studied.
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- Prevalence: the proportion of a population who has a particular disorder or condition at a specific point in time.
- Incidence: a rate of development of new cases of a disorder in a particular at-risk population over a given period of time.
- Parameter: a characteristic or measure obtained by using all the data values from a specific population.
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