critical thinking

process of evaluating claims or hypotheses and making judgments about them on the basis of well-supported evidence

hypothesis

a prediction stated as a testable proposition, usually in the form of an if-then statement

variables

specific factors or characteristics that are manipulated and measured in research

data

numbers that represent research findings and provide the basis for research conclusions

operational definition

a statement of the specific methods used to measure a variable; a detailed explanation of the variable

theory

cluster of explanations of a phenomenon that help predict, explain, and control that behavior

naturalistic observation

method gathering descriptive information involving watching behaviors, without interfering, as they naturally occur

case study

used to collect descriptive data through the intensive examination of a phenomenon in a particular individual, group, or setting (particularly useful for rare or complex phenomena)

survey

questionnaire or interview administered to a large group; designed to obtain descriptions of peoples' behaviors/beliefs

correlational studies

research method that examines relationships between variables in order to analyze trends in data, test predictions, etc. (they do NOT discern cause and effect relationships)

experiment

the only research method to show causation, this involves obtaining a random sample of subjects and using control and experimental groups; allows a researcher to control the data-collection process

independent variable

controlled by the researcher, experienced by the control group, this is what the researcher thinks will HAVE an effect on some other behavior

dependent variable

behavior affected by another variable, it is observed and measured (usually before and after and experiment takes place)

experimental group

receives the critical part of the experiment (the independent variable)

control group

provides a baseline for comparison, does not receive critical treatment (independent variable)

experimenter bias

occurs when experimenters ask leading questions or otherwise search for evidence that supports their hypothesis and don't look for evidence that refutes it

random variable

a confounding variable in which uncontrolled factors affected the dependent variable along with or instead of the independent variable

random assignment

random distribution of participants to experimental or control groups - used to distribute the impact of uncontrolled variables randomly, and most likely evenly, across the groups, minimizing the chance they will distort the results

placebo effect

improvement caused by a participant's knowledge and expectations: can be from a treatment that contains nothing known to be helpful, but that nevertheless produces benefits because a person believes it will be beneficial.

confounding variable

any factor that affects the dependent variable, along with or instead of the independent variable

double-blind design

design for research in which neither the experimenter nor the subjects know who is in the experimental or control group

sampling

the process of selecing participants for research who are members of the population the researcher wishes to study

generalize

to apply the results of one's study to people beyond just the researcher's sample

representative sample

a group of subjects whose characteristics fairly reflect the characteristics of the population they belong to

random sample

a group of subjects selected froma population whose members all had an equal chance of being selected

biased sample

a group of research subjects selected froma population whose members did not all have an equal chance of being chosen

sampling error

part of a sampling process that results in a biased sample

convenience sample

when researchers draw participants from the populations that are readily available to them

twin studies

study the heredity-environment question by comparing the similarity seen in identical twins with those of nonidentical pairs

descriptive statistics

numbers that describe and summarize a set of research data

inferential statistics

set of mathematical procedures that help researchers learn if their research data reflects a true relationship or could be due to random chance

mode

measure of central tendency that is the value that occur most frequently in a data set

median

measure of central tendency that is the halfway point in a set of data

mean

measure of central tendency that is the arithmetic average of the scores in a set of data

range

measure of variability that is the difference between the highest and lowest values in a set of data

standard deviation

measure of variability that is the average difference between each score and the mean of the data set (demonstrates consistency)

correlation

the degree to which one variable is related to another

correlation coefficient

a statistic (r) that summarizes the strength and direction of a relationship between two variables

statistical significance

a term used to describe research results that have been shown by a statistical test to be UNLIKELY to be due to random chance

ethics

code used by psychologists dictating that they minimize discomfort or risk for research participants