common cause
a variable which affects two variables at the same time to make it look like they are casually related
concept
an abstract system of meaning that enables us to perceive a phenomenon in a certain way
content analysis
the research method of extracting data from written documents or other recorded materials such as films and TV programs
control group
in an experiment, the group not exposed to the independent variable that is introduced to the experimental group
control variable
variable added to the casual analysis to see if a relationship between an independent and a dependent variable depends on its level
dependent variable
a variable that is changed or influenced by another variable
experimental design
a scientific procedure in which at least two matched groups, differing only in the variable being studied, are used to collect and compare data
experimental group
in an experiment, the group to which an independent variable is introduced in the control group
hypothesis
a concrete statement about the relationship between variables that can be put to an empirical test
independent variable
a variable that causes a change or variation in a dependent variable
indirect relationship
a relationship between the independent and dependent variables which is mediated by a third variable
interaction
a pattern in which the relationship between two variables depends upon the level of the third variable; we say there is an interaction between the control and independent variables
intervening variable
variable that is affected by an independent variable an that in turn affects the dependent variable
mean
a measure of central tendency computed by adding the figures and dividing by the number of figures, also known as the average
methodology
the rules and procedures to guide research
negative relationship
a relationship between two variables such that an increase in one variable is accompanied by a decrease in the other, compare with positive relationship
observational research
research in which the researcher watches what is happening and makes no attempt to control or modify the activity being observed
operational definition
a definition of a concept or variable such that it can be measured
path diagram
a figure representing casual relationships among two or more variables using casual arrows
population
the entire group, cases, or people the researcher is interested in for generalizing his/her findings
positive relationship
a relationship between two variables in which an increase in one variable is accompanied by an increase in the other
proposition
a statement of the relationship between two or more abstract concepts
qualitative methods
the gathering and reporting of non-numerical data used to determine the essential characteristics, properties, or process of something or someone
quantitative methods
the gathering and reporting of data based on numbers or amounts of something
random sample
a sample selected in such a way that every member of a population has an equal chance of being chosen
reliability
the extent to which repeated observations of the same phenomena yield similar results
representative sample
a sample which reflects the characteristic of the population
sample
a number of individuals or cases drawn from the population
scientific method
a procedure that involves systematically formulating problems, collecting data through observation and experiment, and devising and testing hypotheses
secondary analysis
the use of existing information that was gathered or exists independently of one's own research
spurious relationship
a seemingly casual relationship between two variables in which they are both affected by a third variable without any casual relationship between each other
stratified sampling
sampling in which a population is divided into groups and then subjects are chosen at random from within those groups
survey research
a quantitative research technique that involves asking people questions about the subject being surveyed
systematic sampling
obtaining a sample from a population by following a specific pattern of selection, such as choosing every tenth person
theory
a set of logically and systematically interrelated propositions that explain a particular process or phenomenon
validity
the extent to which observation actually measure what they are suppose to measure
variable
any concept with two or more values which vary from one case to another