Module 2 (Research Strategies: How Psychologists Ask and Answer Questions)

standard deviation

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

scatterplot

a graphed cluster of dots, each of which represents the values of two variables. The slope of the points suggests the direction of the relationship between the 2 variables. The amount of scatter suggests the strength of the correlation(little scatter indicates high correlation)

experiment

a research method in which an investigator manipulates one or more factors (independent variables) to observe the effect on some behavior or mental process (the dependent variable). By random assignment of participants, the experiment controls other relevant factors.

random sample

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

operational definition

a statement of the procedures(operations) used to define research variables. (For example, intelligence may be operationally defined as what an intelligence test measures)

correlation coefficient

a statistical measure of the extent to which two factors vary together, and thus how well either factor predicts the other

statistical significance

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

survey

a technique for ascertaining the self-reported attitudes or behaviors of people, usually by questioning a representative, random sample of them

hypothesis

a testable prediction, often implied by a theory

population

all the cases in a group, from which samples may be drawn for a study(except for national studies, this does not refer to a country's whole population)

double-blind experiement

an experimental procedure i which both the research participants and the research staff are ignorant (blind) about whether the research participants have received the treatment or a placebo. (commonly used in drug-evaluation studies)

theory

an explanation using an intergrated set of principles that organizes and predicts observations

case study

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

random assignment

assigning participants to experimental and control conditions by chance, thus minimizing preexisting differences between those assigned to the different groups

placebo effect

experimental results caused by expectations alone, any effect on behavior caused by the administration of an inert substance or condition, which is assumed to be an active agent

naturalistic observation

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

replication

repeating the essence of a research study, usually with different participants in different situations, to see whether the basic finding extends to other participants and circumstances

mean

the arithmetic average of a distribution, obtained by adding the scores and then dividing by the number of scores

control condition

the condition of an experiment that contrasts with the experimental condition and serves as a comparison for evaluating the effect of the treatment

experimental condition

the condition of an experiment that exposes participants to the treatment, that is, to one version of the independent variable

range

the difference between the highest and lowest scores in a distribution

culture

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

independent variable

the experimental factor that is manipulated, the variable whose effect is being studied

dependent variable

the experimental factor- in psychology, the behavior or mental process- that is being measured, the variable that may change in response to manipulations of the independent variable

median

the middle score in a distribution, half the scores are above it and half are below it

mode

the most frequently occurring score in a distribution

illusory correlation

the perception of a relationship where none exists

hindsight bias

the tendency to believe, after learning an outcome, that one would have foreseen it (also known as the I-knew-it-all-along phenomenon)

false consensus effect

the tendency to overestimate the extent to which others share our beliefs and behaviors

critical thinking

thinking that does not blindly accept arguments and conclusions. Rather it examines assumptions, discerns hidden values, evaluates evidence, and assesses conclusions