Science Practices

Dr. Eaker

Descriptive research method

describe behaviors of people or situations with NO manipulation of variables

> case studies, naturalistic observations, and surveys

Correlational research method

associate different factors or variables, with NO manipulation of variables

Experimental research method

manipulate variables to discover their effects

> variables, types of correlation, coefficient, scatterplot

Operational definition

carefully worded statement of exact procedures used in study

> allows for replication of study, which is important to affirm findings

Population

group of people with shared characteristic(s) that a study wants to describe

Random sample

method in which each member of subset has equal chance of being chosen

Sampling bias

some members of population is more likely to be chosen for a study than others

• convenience sampling

Illusory correlation

the phenomenon of perceiving a relationship between variables, even when no such relationship exists

Case study

technique that studies an individual in depth to try and reveal universal principals

Naturalistic observation

technique of observing and recording behavior in naturally occurring situations, without manipulation

Survey

a research technique that questions a sample of people to collect information about their attitudes or behaviors

Variables

Independent - the experimental factor that is manipulated; the variable whose effect is being studied

Dependent - variable that changes in response to the changes in the independent variable; the effect, output, or what happens during the experiment

Types of correlation

Positive correlation - when the two variables move in the same direction (as one increases, so does the other)

Negative correlation - when the two variables move in opposite directions (as one increases, the other decreases)

Scatterplot

a graphed cluster of dots, each representing the values of two variables

Correlation coefficient

statistical measure of the strength of a linear relationship between 2 variables, between -1 to 1

Experiment

research method where investigator manipulates one or more factors to observe the effect on some behavior or mental process, using random assignment

Experimental group

in an experiment, the group that is exposed to the treatment, at least a version of the independent variable

Control group

in an experiment, the group that is not exposed to the treatment and is compared for evaluating the effect of treatment

Random assignment

assigning participants to experimental and control groups by chance, thus minimizing pre-existing differences between the different groups

Independent variable

in an experiment, the factor that is manipulated; the variable whose effect is being studied

Dependent variable

in an experiment, the factor that is measured, and may change in response to the manipulation of the independent variable

Confounding variable

a factor other than the factor being studied, that might influence a study's results

Double-blind procedure

experimental procedure when both the researcher and the participants do not know which group has received the treatment or placebo

Placebo effect

just thinking about receiving treatment can impact people's expectations/behavior/symptoms/mood, even when no treatment was actually given

Validity

the extent to which a test/experiment measures or predicts what it is supposed to

Longitudinal study

study of same population over long periods of time

type of correlational study

used to study development over time

Cross sectional study

study of several different ages / generations at the same time

type of correlational study

used to determine the prevalence of a disease, phenomena, or opinion of a population