Studies generated from previous research studies in which the research is produced to validate findings, increase generalizability, and/or eliminate or minimize limitations
Replication studies
Statements of the disparity between what is known and what needs to be known and addressed by the research
Problem statements
Declarative and objective statements that indicate the general goal of the study and often describe the direction of the inquiry
Purpose statements
A question that outlines the primary components that will be studied and guides the design and methodology of the study
Research question
A type of research question that is posed to compare one or more interventions to specific outcomes
Analytic question
Research designed to quantify the strength and the direction of the relationship of two variables in a single subject or the relationship between a single variable in two samples
Correlation studies
Studies planned by the researcher for collection of primary data for the specific research and implemented in the future
Prospective studies
A study conducted using data that have already been collected about events that have already happened. These secondary data were originally collected for a purpose other than the current research
Retrospective study
Retrospective studies are less expensive than prospective studies and are often good starting points for exploratory research questions.
Prospective studies are indicated by research questions that focus on conditions that occur often and with relatively short follow-up periods
Analytic studies are logical for questions answered with numbers or with measurements
A restatement of the research question in a form that can be analyzed statistically for significance
Hypothesis
Two essential aspects of a good hypothesis are:
A statement of an expected relationship
An identification of a direction of interest
A statement of the research question that declares there is no difference between groups
Null hypothesis
A two-sided statement of the research question that is interested in change in any direction
Nondirectional hypothesis
A one-sided statement of the research question that is interested in only one direction of change
Directional hypothesis
Sometimes called two sided hypotheses, these are appropriate for exploratory research questions or randomized trials of interventiosn.
Nondirectional hypothesis
These are more rigorous tests than directional hypotheses
Nondirectional hypothesis
Appropriate for research questions in which there is a great deal of literature or empiracal support for an existing relationship.
Directional hypothesis
Directional hypothesis tests are more liberal than nondirectional ones