R and A Key Terms

variable

a characteristic of condition can have different values across people, situations, or time. Variables can be measured or manipulated

hypothesis

a tentative specific testable statement about the relationship between two or more variables

operational definition

a specific description of how a particular variable is either manipulated or measured in a study

independent variable

the variable (X) that is manipulated in an experiment. The variable predicted to cause an effect on another variable (Y)

dependent variable

the variable (Y) that is measured in an experiment. The variable predicted to be affected by manipulating the independent variable (x)

experimental group

group of participants who are randomly assigned to receive the “treatment” or key manipulation under investigation in an experiment

control group

group of participants who are randomly assigned to have a neutral or baseline experience in an experiment

random assignment

a procedure for assigning participants to the different conditions an experiment using chance. random assignment helps create equivalent groups and reduces the likelihood that preexisting differences between participants confound the results

confounding variables

any variables other than the IV that could be systematically affecting the DV. A variable besides the IV differs between the two conditions of the study (very bad)

constant

any variable in an experiment that is kept the same for all conditions of the study (experimental and control groups) For example the lighting, temperature of the room, friendliness of the experimenter, etc. Such variables are controlled so that they don’t become a confounding variable

correlational study

a study in which at least two variables are measured to assess the relation between them. there is no manipulated variable or random assignment to condition. thus, two variables may covary (as one increases or decreases, so does the other) but there is no way to asses for a cause and effect relation between the variables

sample

the group of participants who actually take part in a research study

population

the larger group of people that researchers are interested in understanding and to whom they want to generalize their findings

random sampling

a method of selecting participants from a population in which members of the population have a known chance of being selected for the sample

construct

an abstract concept or characteristic that researchers want to study but cannot directly observe, such as intelligence or self-esteem. Researchers use operational definitions to specify how constructs will be measured or manipulated