A five-step process for empirical investigation of a hypothesis under conditions designed to control biases and subjective judgements
An approach to research that relies on sensory experience and observations as research data
A testable explanation for a set of facts or observations. In science, a theory is not just speculation or a guess.
A statement predicting the outcome of a scientific study; a statement describing the relationship among variables in a study
Specific descriptions of concepts involving the conditions of a scientific study. Operational definitions are stated in terms of how the concepts are to be measured or what operations are being employed to produce them.
A stimulus condition so named because the experimenter changes it independently of all the other carefully controlled experimental conditions
A process by which chance alone determines the order in which the stimulus is presented.
Pieces of information, especially information gathered by a researcher to be used in testing a hypothesis.
The measured outcome of a study; the responses of the subjects in a study.
In research, this refers to doing a study over to see whether the same results are obtained. As a control for bias, replication is often done by someone other than the researcher who performed the original study.
A kind of research in which the researcher controls all the conditions and directly manipulates the conditions, including the independent variable.
Variables that have an unwanted influence on the outcome of an experiment.
Constraints that the experimenter places on the experiment to ensure that each subject has the exact same conditions.
Each subject of the sample has an equal likelihood of being chosen for the experimental group of an experiment.
Ex post facto
Research in which we choose subjects based on a pre-existing condition.
A type of research that is mainly statistical in nature. Correlational studies determine the relationship (or correlation) between two variables.
A quasi-experimental method in which questions are askede to subjects. When designing a survey, the researcher has to be careful that the questions are not skewed or biased toward a particular answer.
A research method in which subjects are observed in their natural environment
A type of study in which one group of subjects is followed and observed for an extended period of time.
A study in which a representative cross section of the population is tested or surveyed at one specific time.
A research method in which a cross section of the population is chosen and then each cohort is followed for a short period of time.
The researcher allowing personal beliefs to affect the outcome of a study.
The researcher allowing his or her expectations to affect the outcome of a study.
An experimental procedure in which both researchers and participants are uninformed about the nature of the independent variable being administered.
Institutional Review Board
A committee at each institution where research is conducted to review every experiment for ethics and methodology.
Institutional Animal care and Use Committee
A committee at each institution where research is conducted to review every experiment involving animals for ethics and methodology.
A summary chart, showing how frequently each of the various scores in a set of data occurs.
A bar graph depicting a frequency distribution. The height of the bars indicates the frequency of a group of scores
Statistical procedures used to describe characteristics and responses of groups of subjects.
The measure of central tendency most often used to desrcibe a set of data--Calculated by adding all the scores and dividing by the number of scores.
The measure of central tendency for a distribution, represented by the score that separates the upper half of the scores in a distribution from the lower half.
A measure of central tendency for a distribution, represented by the score that occurs more often than any other.
The simplest measure of variability, represented by the difference between the highest and lowest values in a frequency distribution.
A measure of variability that indicates the average difference between the scores and their mean.
A bell-shaped curve, describing the spread of characteristics throughout a population.
A relationship between variables, in which changes in one variable are reflected in changes in the other variable--as in the correlation between a child's age and height.
A number between -1 and 1 expressing the degree of relationship between two variables.
Statistical techniques used to assess whether the results of a study are reliable or whether they might be simply the result of chance. Used to determine whether two or more groups are essentially the same or different.
A sample group of subjects selected by chance.
A sample obtained in such a way that it reflects the distribution of important variables in the larger population in whichc the researchers are interested.
Psychologists accept a difference between the groups as "real" or significant, when the probability it might be due to an atypical sample drawn by chance is less than 5 in 100. (p<.05)