ap psych unit 0 vocab

anecdotal evidence

causally observed incidents that are accepted as useful information; scientifically inadequate, but can offer clues as to areas of investigation that warrant more systematic, controlled research

between-subjects design

a study in which individuals are assigned to only one treatment or experimental condition and each person provides only one score for data analysis

within-subjects design

an experimental design in which the effects of treatments are seen through the comparison of scores of the same participant observed under all the treatment conditions

case study

an in-depth investigation of a single individual, family, event, or other entity; multiple types of data are assembled to understand background, relations, behavior; allow intense analysis of an issue, but limited by not being generalizable

casual ambiguity

also known as third-variable problem; a situation in which it is not known which one (or which set) of several phenomena is the cause of a particular effect

control condition

also known as control group; in an experiment or research design, a condition that does not involve exposure to the treatment or intervention under study

experimental condition

also known as experimental group; a condition that involves exposure to a treatment or experience the control group has not

correlation

the degree of a relationship between two variables

correlation coefficient

a numerical index reflecting the degree of a linear relationship between two variables (where +1 indicates a perfect positive relationship and -1 indicates a perfect negative relationship)

counterbalancing

arranging a series of experimental conditions or treatments in such a way as to minimize the influence of extraneous factors, such as practice or fatigue, on experimental results

demand characteristics

in an experiment or research project, cues that may influence or bias participants' behavior, for example, by suggesting the outcome or response that the experimenter expects or desires

empirical research

also known as empiricism; the approach holding that all knowledge of matters of fact either arises from experience or requires experience for its validation

error

here, any change in a dependent variable not attributable to manipulation of the independent variable

bias

here, a systematic error arising during sampling data collection or data analysis; any deviation of a measured or calculated quantity from its actual value (e.g., the measurement or calculation is unrepresentative of the item of interest)

experimental design

an outline or plan of the procedures to be followed in scientific experimentation in order to reach valid conclusions, with consideration of such factors as participant selection, variable manipulation, data collection, and analysis, and minimization of external variables

quasi-experimental design

an experimental design in which assignment of participants to an experimental group or to a control group cannot be made at random for either practical or ethical reasons; assignment of participants to conditions is usually based on self-selection or by selection by an administrator

extraneous variable

a measurement that is not under investigation in an experiment but may potentially affect the outcome or dependent variable and thus may influence results

confounding variable

an independent variable that is conceptually distinct but empirically inseparable from one or more other independent variables

false consensus effect

the tendency of how individuals frequently overestimate how much others share their beliefs, values, and behaviors; people project their personal ideas and attitudes onto others, assuming they are more common and widespread than they actually are

frequency distribution

a tabular representation of the number of times a specific value or datum point occurs

histogram

a graphical depiction of continuous data using bars of varying height; similar to a bar graph but with blocks on the x-axis adjoining one another as to denote their continuous nature

frequency polygon

a graph depicting a statistical distribution, made up of lines connecting the peaks of adjacent intervals

generalizability

the extent to which results or findings obtained from a sample are applicable to a broader population

hindsight bias

the tendency, after an event has occurred, to overestimate the extent to which the outcome could have been foreseen

hypothesis

an empirically testable proposition about some fact, behavior, relationship. or the like, usually based on a theory, that states an expected outcome resulting from specific conditions or assumptions

illusory correlation

the appearance of a relationship that in reality does not exist; an overestimation of relationship/correlation between two variables

independent variable

the variable in an experiment that is specifically manipulated or is observed to occur before the dependent variable in order to assess its effect or influence

dependent variable

the outcome that is observed to occur or change after the occurrence or variation of the independent variable in an experiment

inferential statistics

a broad class of statistical techniques that allow inferences about characteristics of a population to be drawn from a sample of data from that population while controlling (at least partially) the extent to which errors of inference may be made

descriptive statistics

procedures for depicting the main aspects of sample data without necessarily inferring to a larger population; usually include mean, median, and mode and to indicate central tendency, as well as the range and standard deviation

mean

the numerical average of a set of scores (the sum of all scores divided by the number of scores)

median

the midpoint in a distribution (the score that divides it into two equalized halves)

mode

the most frequently occurring score in a set of data

meta analysis

a quantitative technique for synthesizing the results of multiple studies of a phenomenon into a single study

natural observation

a method that involves observing subjects in their natural environment; look at behavior without intervening

lab observation

the act of conducting studies in a controlled environment to gather data and insights in a controlled setting

normal distribution

a theoretical distribution in which values pile up in the center at the mean and fall off into tails at either end; when plotted, gives the familiar bell-shaped curve

positively skewed distribution

a type of distribution in which most values are clustered around the left tail of the distribution curve while the right tail of the distribution is longer

negatively skewed distribution

a type of distribution in which most values are clustered around the right side of the distribution curve while the left tail of the distribution is longer

null hypothesis

a statement that a study will find no meaningful differences between the groups or conditions under investigation, such that there is no relationship among the variables of interest and that any variation in observed data is the result of chance or random processes

operational definition

a description of something in terms of the operations (procedures, actions, or processes) by which it could be observed and measured

percentile score

the location of a score in a distribution expressed as the percentage of cases in the data set with scores equal to or below the score in question

placebo

a pharmacologically inert substance, such as a sugar pill, that is often administered as a control in testing new drugs; any medical or psychological intervention that is to be "inert" thus making it valuable as a control condition against which to compare the intervention or treatment of interest

placebo effect

a clinically significant response to a therapeutically inert substance or nonspecific treatment, deriving from the recipient's expectations or beliefs regarding the intervention

population

also known as target population; the population that a study is intended to research and to which generalizations from samples are to be made

positive correlation

a relationship between two variables in which both rise and fall together

negative correlation

a relationship between two variables in which the value of one variable increase as the value of the other decreases

principle of falsifiability

the logical possibility that an assertion, hypothesis, or theory can be shown to be false by an observation or experiment

random assignment

in experimental design, the assignment of participants or units to the different conditions of an experiment entirely at random, so that each participant has an equal likelihood of being assigned to any particular condition

random sample

also known as simple random sample; a group selected by a process of selecting a sample of study participants from a larger potential group of eligible individuals

stratified sample

also known as stratified random sample; a group selected from a population comprised of various subgroups in such a way that each subgroup is represented

reliability

the trustworthiness or consistency of a measure; the degree to which a test or other measurement instrument is free from random error, yielding the same results across multiple applications to the same sample

validity

the degree to which empirical evidence support the adequacy and appropriateness of conclusions drawn from some form of assessment; based upon correlation with an accepted standard, the conceptual variable underlying a test, and the subject matter of a test

replication

the repetition of an original experiment or research study to verify or bolster confidence in its results

scatterplot

also known as scatter diagram; a graphical representation of the relationship between two continuously measured variables in which one variable is arrayed on each axis and a dot or other symbol is placed at each point where the values of the variables intersect

single-blind study

a procedure in which participants are unaware of the experimental conditions under which they are operating

subject expectancy effect

a form of reactivity that occurs when a research subject expects a given result and therefore unconsciously affects the outcome or reports the expected result

double-blind study

a procedure in which both the participants and the researchers interacting with them are unaware of the particular experimental conditions

experimenter expectancy effect

an effect in which a researcher's expectations about the findings of their research are inadvertently conveyed to participants and influence their responses

social desirability bias

the tendency of individuals to present themselves in a manner that will be viewed favorably by others

sampling bias

a systematic and directional error involved in the choice of units, cases, or participants from a larger group for study

volunteer bias

any systematic difference between individuals who volunteer to be in a study versus those who do not, which may potentially render the resulting group or sample of participants unrepresentative of the larger population

standard deviation

a measure of the variability of a set of scores or values within a group, indicating how narrowly or broadly they deviate from the mean

range

a measure of dispersion obtained by subtracting the lowest score in a distribution from the highest score

standard score

also known as a z-score; a set of scores that have the same mean and standard deviation so they can be compared

statistical significance

the degree to which a research outcome cannot reasonably be attributed to the operation of chance or random factors

p-value

also known as probability value, a number describing the likelihood of obtaining the observed data under the null hypothesis of a statistical test

theory

a principle or body of interrelated principles that purports to explain or predict a number of interrelated phenomena; a set of logically related explanatory hypotheses that are consistent with a body of empirical facts and that may suggest more empirical relationships