Categorical Variable Usually an independent or predictor variable that contains values indicating membership in one of several possible categories. Synonym for interval variable. Any variable that has a limited number of distinct values and which cannot be divided into fractions, is a. discontinuous variable. //--> Quantitative variables are again of two types: discrete and continuous. An extraneous variable that an investigator does not wish to examine in a study. A variable that is an inherent part of the system being studied and that is deter- mined from within the system. Learn types of research psychology variables with free interactive flashcards. Thus the investigator controls this variable. The presumed "cause" on a nonexperimental study. Also called a covariate. A variable that influences, or moderates, the relation between two other variables and thus produces an interaction effect. A variable that obscures the effects of another variable. For example, a household could have three or five children, but not 4.52 children. A variable that is not restricted to particular values (other than limited by the accuracy of the measuring instrument). There will be a difference between male and female participants in the number of basketball hoops scored. Strictly speaking, this includes all but binary variables. The dependent variable is the variable that the researcher measures upon alteration of the independent variable. Created by recoding categorial variables that have more than two categories into a series of binary variables. E.g., gender (male or female), marital status (married, single, divorced, widowed). Male participants will score more basketball hoops than female participants. Independent variables affect or have an impact on other variables. Generally, variables are applied in psychological experiments to determine if changes to one element cause changes to another. For example, in an experiment on the impact of sleep deprivation on test performance, sleep deprivation would be the independent variable. These are the variables that the experimenter measures - their value depends on how the independent variable has been set. E.g., reaction time, neuroticism, IQ. There will be a difference in the number of items correctly recalled from a list between participants who have had memory improvement training and those who have not. In the above example the dependent variable is short-term memory capacity. In a scientific theory, particularly within psychology, a hypothetical construct is an explanatory variable that is not directly observable. google_ad_slot = "5288332367"; There will be no difference between participants who have been trained in memory improvement strategies and those who have not in the number of items correctly recalled from a list. Synonym for criterion variable. As previously discussed, any variable that can potentially play a role in the outcome of a study but which is not part of the study is called a confounding variable. It is hypothesized to exist in order to explain other variables, such as specific behaviors, that can be observed. A variable used to rank a sample of individuals with respect to some characteristics, but differences (i.e., intervals) and different points of the scale are not necessarily equivalent. Researchers must be aware that variables outside of the independent variable(s) may confound or alter the results of a study. The usual reference is to categorical variables with more than two categories. /* large rect blue text media */ A causal system says nothing about its exogenous variables. variables. Usually an independent or predictor variable that contains values indicating membership in one of several possible categories. For example, number of trials need by a student to learn a memorization task. Participants whop have been trained in a memory improvement strategy will correctly recall more items from a list than participants who have not been trained. The independent variable is the variable the experimenter changes or controls and is assumed to have a direct effect on the dependent variable. Strictly speaking, "independent vari- able" should not be used when writing about nonexperimental designs. google_ad_width = 336; Quantitative variables are again of two types: discrete and continuous. google_ad_slot = "6938338200"; google_ad_height = 280; Strictly speaking, "dependent variable" should not be used when writing about nonex- perimental designs. An underlying variable that cannot be observed. Dependent variables need to be operationalised before they can be measured. There are three types of categorical variables: binary, nominal, and ordinal variables. We can look at indicators such as vocabulary size, success in one's occupation, IQ test score, ability to play complicated games (e.g., bridge) well, writing ability, and so on. Var_2: 1=divorced, widowed, or separated, 0=otherwise. Income, temperature, age, or a test score are examples of continuous. There is no way to determine if differences in reading between the two classes were caused by either or both of the independent variables. Often used in correlational studies. Extraneous Variable Extraneous variables are undesirable variables that influence the relationship between the variables an experimenter is examining. //-->, Keywords: operationalising variables, operationalizing variables, dependent variable, independent variable, extraneous variable, directional hypothesis, nondirectional hypothesis, null hypothesis, PsychTeacher(UK) - the number one site for A Level Psychology, Variables and hypotheses in psychology research. Variables that can have more than two possible values.