Organized sets of concepts that explain phenomena

Prediction of how two or more factors are likely to be related.

Repetition of the methods used in a previous experiment to see whether the same methods will yield the same results.

The factor the researcher manipulates in a controlled experiment (the cause).

The behavior or mental process that is measured in an experiment or quasi-experiment (effect).

All of the individuals in the group to which the study applies.

The subgroup of the population that participates in the study.

Choosing of members of a population so that every individual has an equal chance of being chosen to participate in a study.

The subgroup of the sample that receives the treatment or independent variable.

The comparison group; the subgroup of the sample that is similar to the experimental group in every way except for the presence of the independent variable.

Manipulation of an independent variable under controlled conditions that measurement of its effects on a dependent variable.

Measurement of a dependent variable when random assignment to groups is not possible.

Careful observations of humans or animals in real-life situations.

Obtain large samples of abilities, beliefs, or behaviors at a specific time and place.

Intensive investigation of the behavior and mental processes associated with a specific person or situation

Division of the sample into groups so that every individual has an equal chance of being put in any group or condition.

Factors that cause differences between the experimental group and the control group other than the independent variable.

A description of the specific procedure used to determine the presence of a variable.

A phenomenon that occurs when a researcher's expectations or preferences about the outcome of a study influence the results obtained

Clues participants discover about the purpose of the study that suggest how they should respond.

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

Research design in which neither the experimenter nor the participants know who is in the experimental group and who is in the control group.

A physical or psychological treatment given to the control groupo that resembles the treatment given to the experimental group, but that contains no active ingredient.

A response to the belief that the independent variable will have an effect, rather than the actual effect of the independent variable, which can be a confounding variable.

Consistency or repeatability of results.

The extent to which an instrument measures or predicts what it is supposed to measure or predict.

A field that involves the analysis of numerical data about representative samples of populations.

Numbers that summarize a set of research data obtained from a sample.

An orderly arrangement of scores indicating the frequency of each score or group of scores.

Average or most typical scores of a set of research data or distribution.

Most frequently occurring score in a set of research data ('quick and dirty')

The middle score when a set of data is ordered by size.

The arithmetic average of a set of scores.

The spread or dispersion of a set of research data or distribution.

The difference between the largest score and the smallest score ('quick and dirty').

Measures the average difference between each score and the mean of the data set.

Bell-shaped curve that represents data about how lots of human characteristics are dispersed in the population.

The percentage of scres at or below a particular score (from 1 to 99).

A statistical measure of the degree of relatedness or association between two sets of data that ranges from -1 to +1.

Statistics that are used to interpret data and draw conclusions.

The condition that exists when the probability that the observed findings are due to chance is less than 1 in 20 or 1 in 100 for those with stricter standards

Suggested rules for acting responsibly and morally when conducting research or in clinical practice.

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