Unit 2: Research Methods: Thinking Critically with Psychological Science

Module: 4,5,6,7,8

Hindsight Bias

the tendency to believe after leaving an outcome, that one would have foreseen it. ( I knew it all along)

Theory

an explanation using an integrated set of principles that organize observations and predict behaviors or events

Hypothesis

a testable prediction, often implied by a theory

Operational Definition

a carefully worded statement of the exact procedures (operations) used in a research study.

Replication

Repeating the essence of a research study, usually with different participants in different situations to see whether the basic finding can be reproduced

Case Study

a descriptive technique in which one individual or group is studied on depth in the hope of revealing universal principles

Naturalistic Observation

a descriptive technique of observing and recording behavior in naturally occurring situations without trying to manipulate or control the situation

Survey

descriptive technique for obtaining the self-reported or behaviors of a particular group, usually by questioning a representative, random sample of the group

Sampling Bias

a flawed sampling process that produces an unrepresentative sample

Populations

all those in a group being studied from which samples may be drawn

Random Sampling

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

Correlation

measure of the extent to which two factors vary together, and thus of how well either factors predict the other

Correlation Coefficient

a statistical index of the relations between two things (from -1.00 to 1.00)

Variable

anything that can vary and is feasible and ethical to measure

Scatterplot

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

Illusory Correlation

perceiving a relationship where none exist or perceiving a stranger -than- actual - relationship

Regression toward the mean

the tendency for extreme or unusual scores or events to fall back (regress) toward the average

Experiment

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

Experimental group

in an experiment, the group exposed to the treatment, that is, to one version of the independent variable

Control group

in an experiment, the group not exposed to the treatment: contrast with the experimental group and serves as a comparison for evaluating the effect of the treatment

Random Assignment

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

Double-Blind procedure

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A Double-Blind procedure is an experimental technique where both the research participants and the research staff are unaware of whether the participants have received the treatment or a placebo. This method is commonly used in drug-evaluation studies.

Placebo

experimental results caused by expectations alone;any effect on behavior caused by the administrator of an inert substance or condition which the recipient assumes is an active agent

Independent variable

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

Confounding variable

a factor other than the the factor being studies that might influence a study’s result

Dependant Variable

in an experiment the outcome that is measures; the variable that may change when the independent variable is manipulated

Validity

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

informed consent

giving potential participants enough information about a study to enable them to choose whether they wish to participate

Debriefing

the postexperimental explanation of a study including its purpose and any deceptions to its participants

Descriptive statistics

numerical data used to measure and describe characteristics of groups. Including measures of central tendency and measures of variation

Histogram

a bar graph depicting a frequency distribution

Mode

the most frequently occuring scores in a distribution

Mean

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

Median

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

Skewed distribution

a representation of scores that lack symmetry around their average value

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;most scores fall near the mean and fewer near the extremes

Inferential Statistics

numerical methods used to determine whether research data support a hypothesis or whether results were due to chance.

Statistical significance

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