hindsight bias

the tendency to believe, after learning an outcome, that one would have foreseen it (AKA i-knew-it-all-along phenomenon)

critical thinking

thinking that examines assumptions, discerns hidden values, evaluates evidence, and assesses conclusions

theory

an explanation using an integrated set of principles that organizes observations and predicts behaviors or events

hypothesis

a testable predictions, often implied by a theory

operational definition

a statement of the procedures used to define research variables

replication

repeating the essence of a research study to see whether the basic finding extends to other participants and circumstances

case study

an observation technique in which one person is studied in depth in the hope of revealing universal principles

survey

a technique for ascertaining the self-reported attitudes or behaviors of a particular group

population

all the cases in a group being studied

random sample

a sample that fairly represents a population because each member has an equal chance of inclusion

naturalistic observation

observing and recording behavior in naturally occurring situations without trying to manipulate and control the situation

correlation

a measure of the extent to which two factors very together

correlation coefficient

a statistical index of the relationship between two things (from -1 to +1)

scatterplots

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

illusory correlation

the perception of a relationship where none exists

experiment

a research method in which an investigator manipulates one or more factors to observe the effect of some behavior or mental process

random assignment

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

double-blind procedure

an experimental procedure in which both the research participants and the research staff are ignorant about whether the research participants have received the treatment or a placebo

placebo effect

experimental results caused by expectations alone

experimental group

the group that is exposed to the treatment

control group

the group that is not exposed to the treatment

independent variable

the experimental factor that is manipulated

dependent variable

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

mode

the most frequently occurring score(s) in a distribution

mean

the arithmetic average of a distribution

median

the middle score in a distribution

range

the difference between the highest and lowest scores in a distribution

standard deviation

a computed measure of how much scores vary around the mean score

normal curve

a symmetrical, bell-shaped curve that describes the distribution of many types of data

statistical significance

a statistical statement of how likely it is that an obtained result occurred by chance

culture

the enduring behaviors, ideas, attitudes, and traditions shared by a group of people and transmitted from one generation to the next