The tendency to believe, after learning an outcome, that one would have foreseen it
double blind procedure
An experimental procedure in which both the research participants and the research staff are ignorant about whether the research participants have received the treatment or a placebo. Commonly used in drug-evaluation studies
The experimental factor that is manipulated-the variable whose effect is being studied
The outcome factor-the variable that may change in response to manipulations of the independent variable
The most frequently occurring score(s) in a distribution
The arithmetic average of a distribution, obtaining by adding the scores and then dividing by the number of scores
The middle score in a distribution-half the scores are above it and half are below it
A computed measure of how much scores vary around the mean score
Assigning participants to experimental and control conditions by chance ,thus minimizing preexisting differences between those assigned to the different groups
A sample that fairly represents a population because each member has an equal chance of inclusion
A graphed cluster of dots, each of which represents the values of two variables. The slope of the points suggests the direction of the relationship between the two variables. The amount of scatter suggests the strength of the correlation
The perception of a relationship where none exists
An observation technique in which one person is studied in depth in the hope of revealing universal principles
A technique for ascertaining the self-reported attitudes or behaviors of people, usually by questioning a representative, random sample of them
Observing and recording behavior in naturally occurring situations without trying to manipulate and control the situation
A measure of the extent to which two factors vary together, and thus of how well either factor predicts the other. The correlation coefficient is the mathematical expression of the relationship, ranging from -1 to +1
A research method in which an investigator manipulates one or more factors (independent variables) to observe the effects on some behavior or mental process (the dependent variable). By random assignment of participants, the experimenter aims to control other relevant variable
Repeating the essence of a research study, usually with different participants in different situations, to see whether the basic finding extends to other participants and circumstances
A statistical statement of how likely it is that an obtained result occurred by chance
A statement of the procedures used to define research variables. Ex human intelligence -- what an intelligence test measures.
Thinking that does not blindly accept arguments and conclusions. Rather, it examines assumptions, discerns hidden values, evaluates evidence, and assesses conclusions.
An explanation using an integrated set of principles that organizes and predicts observations
A testable prediction, often implied by a theory
All the cases in a group, from which samples may be drawn for a study
Items selected at random from a population and used to test hypotheses about the population
A statistical index of the relationship between two things (from -1 to +1)
Experimental results caused by expectations alone; any effect on behavior caused by the administration of an inert substance or condition, which the recipient assumes is an active agent.
Any effect that seems to be a consequence of administering a placebo
In an experiment, the group that is exposed to the treatment, that is, to one version of the independent variable.
In an experiment, the group that is not exposed to the treatment; contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment.
A factor other than the independent variable that might produce an effect in an experiment.
The difference between the highest and lowest scores in a distribution
A symmetrical, bell-shaped curve that describes the distribution of many types of data; most scores fall near the mean (68% fall within one standard deviation of it) and fewer near the extremes
Numerical methods used to determine whether research data support a hypothesis or whether results were due to chance
The enduring behaviors, ideas, attitudes, and traditions shared by a large group of people and transmitted from one generation to the next
An ethical principle requiring that research participants be told enough to enable them to choose whether they wish to participate
The post-experimental explanation of a study, including its purpose and any deceptions, to its participants