2.2 psychologists use descriptive, correlational, and experimental research designs to understand behavior

research designs

the specific method a researcher uses to collect, analyze, and interpret data

descriptive research

research designed to describe how things are right now

correlational research

research designed to discover relationships among variables and to allow the prediction of future events from present knowledge

experimental research

research in which initial equivalence among research participants in more than one group is created, followed by a manipulation of a given experience for these groups and a measurement of the influence of the manipulation

three types of descriptive research

1. case study

2. survey

3. naturalistic observation

case studies

the use of multiple sources of data to gain a better understanding of a person, group, or event

survey

a research method where a group of volunteers are selected from a population to answer questions about themselves, like opinions, values, or beliefs

naturalistic observation

research based on the observation of everyday events

population

all the people that the researcher wishes to know about

random sample

people randomly chosen to participate in the survey or research project

scatterplot

a visual image of the relationship between two variables, a point is plotted for each intersection of scores for the two variables

independent variable

the causing varibale that is created, manipulated by the experimenter

dependent variable

a measured variable that is expected to be influenced by the experimental manipulation

hypothesis

written as an if/then statement

• if - independent variable

• then - dependent variable

random assignment

where each participant is randomly assigned to a condition