AP Psychology (AAQ Vocab)

experiment

A research method in which an investigator manipulates one or more factors to observe the effect on some behavior or mental process

experimental group

In an experiment, the group that is exposed to the treatment, that is, to one version of the independent variable.

control group

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.

independent variable

The experimental factor that is manipulated; the variable whose effect is being studied.

dependent variable

The outcome factor; the variable that may change in response to manipulations of the independent variable.

confouding variable

a factor other than the independent variable that might produce an effect in an experiment

Correlation

A measure of the extent to which two factors vary together, and thus of how well either factor predicts the other.

correlation coefficient

a statistical index of the relationship between two things (from -1 to +1)

case study

an observation technique in which one person is studied in depth in the hope of revealing universal principles

naturalistic observation

observing and recording behavior in naturally occurring situations without trying to manipulate and control the situation

meta-analysis

a statistical technique that averages the results of two or more studies to see if the effect of an independent variable is reliable

operational definition

a carefully worded statement of the exact procedures used in a research study

mean

the arithmetic average of a distribution, obtained by adding the scores and then dividing by the number of scores

Median

the middle score in a distribution; half the scores are above it and half are below it

Mode

the most frequently occurring score(s) in a distribution

range

the difference between the highest and lowest scores in a distribution

standard deviation

a computed measure of how much scores vary around the mean score

percentile rank

the percentage of scores below a specific score in a distribution of scores

Skewness

The extent to which cases are clustered more at one or the other end of the distribution of a quantitative variable rather than in a symmetric pattern around its center

statistical significance

a statistical statement of how likely it is that an obtained result occurred by chance

effect size

a measure of the strength of the relationship between two variables or the extent of an experimental effect

Institutional Review Board (IRB)

A group made up of at least one scientist, one nonscientist, and one member not affiliated with the institution that reviews all psychological research at that institution and decides whether it meets ethical guidelines; all research must be approved by the IRB before it is conducted

Protection from harm

the right of research participants to be protected from physical or psychological harm

Avoiding deception

Participants should not be deceived unless there is specific scientific or medical justification.

Confidentiality

the act of holding information in confidence, not to be released to unauthorized individuals

Debriefing

the post-experimental explanation of a study, including its purpose and any deceptions, to its participants

operational definition

a statement of the procedures used to define research variables

sampling bias

a flawed sampling process that produces an unrepresentative sample

random sample

a sample that fairly represents a population because each member has an equal chance of inclusion

Population

all those in a group being studied, from which samples may be drawn

random assignment

assigning participants to experimental and control conditions by chance, thus minimizing preexisting differences between those assigned to the different groups

Single-blind procedure

research design in which participants don't know whether they are in the experimental or control group

double-blind procedure

an experimental procedure in which both the research participants and the research staff are ignorant (blind) about whether the research participants have received the treatment or a placebo. Commonly used in drug-evaluation studies.

placebo effect

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.

Quantitative Research

research that collects and reports data primarily in numerical form

Qualitative Research

research that relies on what is seen in field or naturalistic settings more than on statistical data

informed consent/assent

giving potential participants enough information about a study to enable them to choose whether they wish to participate