AP Psychology: Science Practices FULL

Unit 0: Science Practices Terms

Hypothesis

a testable prediction, often implied by a theory

Generalizability

the degree to which research results can be applied in a broader context (Can the results apply to most contexts? Most people? Most of the time?)

Independent variable

a factor in an experiment that is manipulated by the experimenter (the variable whose effect is being studied)

Dependent variable

the variable that may change in response to manipulations of the independent variable

Confounding variable

an unmeasured variable that might influence a study's results

Manipulation of variables

a deliberate operation performed by the experimenter, sets predetermined experimental conditions (the independent variable) on at least one group of subjects

Random assignment

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

Quantitative data

a measure that reflects a numeric amount (numerical data)

Qualitative data

a measure that describes or characterizes an attribute (non-numerical data)

Informed consent

an ethical principle that research participants be told enough to enable them to choose whether they wish to participate

Informed assent

the agreement of someone not able to give legal consent to participate in a research activity (e.g., a minor)

Confidentiality

a researcher's agreement with participants, through informed consent, about how identifiable private information will be protected and ethically used

Institutional review

when a study is examined for ethical concerns by a committee knowledgeable about research and clinical practice

Protection from harm

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

Deception

misleading participants about the true purpose of a study or the things that will actually happen in a study

Debriefing

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

Eugenics

a set of beliefs and practices that aim to improve the genetic quality of a human population

Central tendency

a number that describes something about the "average" score of a distribution (mean, median, mode)

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 value that occurs most frequently in a given data set.

Variation

the dispersion among data values (i.e., how far apart they are from each other)

Percentile rank

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

Range

the difference between the highest and lowest scores in a distribution

Normal curve

a symmetrical, bell-shape 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 and fewer near the extremes

Bimodal distribution

a distribution with two peaks because the data set has two different modes

Standard deviation

a measure of variability that describes an average distance of every score from the mean; a small standard deviation indicates data are clustered tightly around the mean, and a high deviation indicates the results are more spread out

Regression toward the mean

the tendency of results that are extreme by chance on first measurement (i.e., extremely higher or lower than the average) to move closer to the average when measured a second time

Positive skew

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

Negative skew

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

Scatterplot

a graphed cluster of dots, each of which represents the values of two variables

Correlation

a measure of the relationship between two variables (i.e., how two variables move in relation to one another)

Positive Correlation

a relationship in which one variable decreases as the other variable decreases, or one variable increases while the other increases

Negative Correlation

a relationship in which two variables move in opposite directions (e.g., as variable A increases, variable B decreases)

Correlation coefficient

a statistical measure between -1 and 1 that tells the strength and direction of a relationship between variables (i.e., it reflects how similar the measurements of two or more variables are across a dataset)

Population

the entire group a researcher wants to draw conclusions about through a study

Sample

a selected subset of a population that will be part of a research study

Representative sample

a selected subset of a population that accurately reflects the characteristics of the population as a whole

Random sampling

when members from a population are chosen in a such way that each individual in the population has an equal chance of being selected to be in the sample

Convenience sampling

when a researcher chooses a sample based on people who are readily available to participate

Representation of participants

an indication of how well a sample of participants in a study represents the larger population researchers are interested in

Experimental group

the group in an experiment that receives the variable being tested

Control group

the group in an experiment that does not receive the variable being tested

Single-blind study

a study in which the participants are unaware of whether they are in the control group or the experimental group, but the researcher knows the members in each group

Double-blind study

study in which neither the experimenter nor the subjects know which subjects are in the experimental and control groups

Operational definition

a clear, objective, and complete description of how the variables in a research study are measured and defined

Case study

a research design involving an in-depth and detailed examination of a single subject or small group

Meta-analysis

a statistical method that combines the results of multiple studies to reveal patterns and draw general conclusions

Naturalistic observation

a descriptive technique of observing and recording behavior in naturally occurring situations without trying to manipulate and control the situation

Structured interviews

a method of gathering information that involves asking a set of predetermined questions in a predetermined order to each participant

Likert scale

a rating scale that measures attitudes, opinions, or behaviors by having respondents choose an answer along a continuum

Effect size

a measure of the strength of the relationship between two variables (or the extent of an experimental effect) to help show the significance of a research finding

Statistical significance

shows how likely it is that an obtained result occurred by chance

Replication

repeating a research study to see if the same results can be obtained to show if the original study's findings can be applied to other situations or populations

Peer review

a process in which experts evaluate a research study, article, or manuscript before it gets published to ensure the work meets high academic standards

Falsifiability

the principle that a theory, hypothesis, or assertion can be proven false through observation or experiment--an important characteristic of the scientific method

Placebo

a treatment that appears real, but is designed to have no therapeutic benefit (helps researchers determine the effectiveness of the actual treatment)

Placebo effect

when a person's physical or mental health appears to improve after taking a placebo or 'dummy' treatment (showing that a psychological effect can sometimes be as powerful as other medical treatments)

Overconfidence

a cognitive bias that can lead researchers to overestimate the accuracy of their predictions

Directionality problem

a problem encountered in correlational studies when researchers cannot determine which variable may have caused changes in another variable

Third variable problem

occurs when a correlation between two variables is influenced by an unseen third variable (confounding variable), leading to flawed interpretations

Experimenter bias

when results, data, or participants are impacted because the researcher unknowingly involves their own expectations about the outcome of the study

Social desirability bias

occurs when people answer survey questions according to society's expectations, rather than their own beliefs or experiences

Cultural norms

the shared beliefs, values, and behaviors that are typical for a social group

Confirmation bias

the tendency of individuals to support or search for information that aligns with their beliefs or expectations and ignore information that doesn't

Hindsight bias

when a person convinces themselves that they accurately predicted an event or outcome