data
Measurable outcomes of research studies.
four primary goals of science
description, prediction, control, and explanation
Research
A scientific process that involves the careful collection of data.
scientific method
A systematic and dynamic procedure of observing and measuring phenomena, used to achieve the goals of description, prediction, control, and explanation; it involves an interaction among research, theories, and hypotheses.
theory
A model of interconnected ideas or concepts that explains what is observed and makes predictions about future events. Theories are based on empirical evidence.
hypothesis
A specific, testable prediction, narrower than the theory it is based on.
Occam's Razor (law of parsimony)
when two competing theories exist to explain the same phenomenon, the simpler of the two theories is generally preferred
Step 1
Form a Hypothesis
Step 2
Conduct a Literature Review
Step 3
Design a Study
Step 4
Conduct the Study
Step 5
Analyze the Data
Step 6
Report the Results
Replication
Repetition of a research study to confirm the results.
serendipity
unexpectedly finding things that are valuable or agreeable. In science, it means unexpectedly discovering something important
three main types of research methods
descriptive, correlational, and experimental
variable
Something in the world that can vary and that a researcher can manipulate (change), measure (evaluate), or both
independent variable
The variable that gets manipulated in a research study.
dependent variable
The variable that gets measured in a research study.
operational definition
A definition that qualifies (describes) and quantifies (measures) a variable so the variable can be understood objectively
Descriptive research
Research methods that involve observing behavior to describe that behavior objectively and systematically.
three basic types of descriptive research methods
case studies; observations; and self-report
case study
A descriptive research method that involves the intensive examination of an unusual person or organization.
participant observation
A type of descriptive study in which the researcher is involved in the situation.
naturalistic observation
A type of descriptive study in which the researcher is a passive observer, separated from the situation and making no attempt to change or alter ongoing behavior.
reactivity
The phenomenon that occurs when knowledge that one is being observed alters the behavior being observed.
Hawthorne effect
changes in behavior that occur when people know that others are observing them
observer bias
Systematic errors in observation that occur because of an observer's expectations
experimenter expectancy effect
Actual change in the behavior of the people or nonhuman animals being observed that is due to the expectations of the observer.
Self-report methods
Methods of data collection in which people are asked to provide information about themselves, such as in surveys or questionnaires
socially desirable responding
in which the person responds in a way that is most socially acceptable
Correlational studies
A research method that describes and predicts how variables are naturally related in the real world, without any attempt by the researcher to alter them or assign causation between them.
positive correlation
A relationship between two variables in which both variables either increase or decrease together.
negative correlation
A relationship between two variables in which one variable increases when the other decreases.
zero correlation
A relationship between two variables in which one variable is not predictably related to the other.
directionality problem
A problem encountered in correlational studies; the researchers find a relationship between two variables, but they cannot determine which variable may have caused changes in the other variable
third variable problem
A problem that occurs when the researcher cannot directly manipulate variables; as a result, the researcher cannot be confident that another, unmeasured variable is not the actual cause of differences in the variables of interest.
experiment
A research method that tests causal hypotheses by manipulating and measuring variables.
experimental group
The participants in an experiment who receive the treatment.
control group
The participants in an experiment who receive no intervention or who receive an intervention that is unrelated to the independent variable being investigated.
confound
Anything that affects a dependent variable and that may unintentionally vary between the experimental conditions of a study.
population
everyone in the group the experimenter is interested in.
sample
A subset of a population.
random sampling
gives each member of the population an equal chance of being chosen to participate
convenience sample
this sample consists of people who are conveniently available for the study
random assignment
Placing research participants into the conditions of an experiment in such a way that each participant has an equal chance of being assigned to any level of the independent variable.
selection bias
In an experiment, unintended differences between the participants in different groups; it could be caused by nonrandom assignment to groups.
Culturally sensitive research
Studies that take into account the role that culture plays in determining thoughts, feelings, and actions.
Institutional review boards (IRBs)
Groups of people responsible for reviewing proposed research to ensure that it meets the accepted standards of science and provides for the physical and emotional well-being of research participants.
risk/benefit ratio
an analysis of whether the research is important enough to warrant placing participants at risk
Construct validity
The extent to which variables measure what they are supposed to measure.
External validity
The degree to which the findings of a study can be generalized to other people, settings, or situations.
Internal validity
The degree to which the effects observed in an experiment are due to the independent variable and not confounds.
reliability
The degree to which a measure is stable and consistent over time.
accuracy
The degree to which an experimental measure is free from error.
raw values
data that are as close as possible to the form in which they were collected
descriptive statistics
Statistics that summarize the data collected in a study.
central tendency
A measure that represents the typical response or the behavior of a group as a whole.
mean
A measure of central tendency that is the arithmetic average of a set of numbers.
median
A measure of central tendency that is the value in a set of numbers that falls exactly halfway between the lowest and highest values.
mode
A measure of central tendency that is the most frequent score or value in a set of numbers.
variability
In a set of numbers, how widely dispersed the values are from each other and from the mean.
standard deviation
A statistical measure of how far away each value is, on average, from the mean.
scatterplot
A graphical depiction of the relationship between two variables.
correlation coefficient
A descriptive statistic that indicates the strength of the relationship between two variables.
inferential statistics
A set of assumptions and procedures used to evaluate the likelihood that an observed effect is present in the population from which the sample was drawn.
Meta-analysis
A "study of studies" that combines the findings of multiple studies to arrive at a conclusion.