Chpt. 2 - Research Methods

Cohort Sequential Study

A research method in which a cross section of the population is chosen and then each cohort is followed for a short period of time

Confounding/Extraneous Variables

Variables that have an unwanted influence on the outcome of an experiment

Controls

Constraints that the experimenter places on the environment to ensure that each subject has the exact same conditions

Correlation

A relationship between variables, in which changes in one variable are reflected in changes in the other variable. For example a child's height ___ with his/her age

Correlation Coefficient

A number between -1 and +1 expressing the degree of relationship between two variables

Correlational Study

A type of research that is mainly statistical in nature. ___________ ______determine the relationship between two variables

Cross - Sectional Study

A study in which a representative cross section of the population is tested or surveyed at one specific time

Data

Pieces of information, especially information gathered by a researcher to be used in testing a hypothesis

Dependent Variable

The measured outcome of a study; the responses of the subjects in a study

Descriptive Statistics

Statistical procedures used to describe characteristics and responses of groups of subjects

Double Blind Study

An experimental procedure in which both researches and participants are uniformed about the nature of the independent variable being administered

Empirical Investigation

An approach to research that relies on sensory experience and observation as research data

Ex Post Facto

Research in which we chose subjects based on pre existing conditions

Expectancy Bias

The researcher allowing his or her expectations to affect the outcome of a study

Experiment

A kind of research in which the researcher controls all the conditions and directly manipulates the conditions, including the independent variable

Frequency Distribution

A summary chart, showing how frequently each of the various scores in a set of data occurs

Histogram

A bar graph depicting a frequency distribution. The height of the bars indicates the frequency of a group of scores

Hypothesis

A statement predicting the outcome of a scientific study; a statement describing the relationship among variables in a study

Independent Variable

A stimulus condition so named because the experimenter changes all the other carefully controlled experimental conditions

Inferential Statistics

Statistical techniques (based on probability theory) used to access whether the results of a study are reliable or whether they might simply be the result of chance. ___ ___ are often used to determine whether two or more groups are essentially the same or different

Institutional Animal Care and Use Committee

A committee at each institution where research is conducted to review every experiment involving animals for ethics and methodology

Institutional Review Board

A committee at each institution where research is conducted to review every experiment for ethics and methodology

Longitudinal Study

A type of study in which one group of subjects is followed and observed for an extended period of time (years)

Mean

The measure of central tendency most often used to describe a set of data calculated by adding all the scores and dividing by the number of scores

Median

A measure of central tendency for a distribution, represented by the score that separates the upper half of the scores in a distribution from the lower half

Mode

A measure of central tendency for a distribution, represented by the score that occurs more often than any other

Naturalistic Observation

A research method in which students are observed in their natural environment

Normal Distribution

A bell-shaped curve, describing the spread of characteristics throughout a population

Operational Definitions

Specific descriptions of concepts involving the conditions of a scientific study. Stated in terms of how the concepts are to be measured or what are being employed to produce them

Personal Bias

The researcher allowing personal beliefs to affect the outcome of a study

Random Assignment

Each subject of the sample has an equal likelihood of being chosen for the experimental group of an experiment

Random Presentations

A process by which chance alone determines the order in which the stimulus is presented

Random Sample

A sample group of subjects selected by chance (without biased selection techniques)

Range

The simplest measure of variability, represented by the difference between the highest and the lowest values in a frequency distribution

Replicate

In research, this refers to doing a study over to see whether the same results are obtained. As a control for bias, this is often done by someone other than the researcher who performed the original study

Representative Sample

A sample obtained in such a way that it reflects the distribution of important variables in the larger population in which the researchers are interested - variables such as age, income level, ethnicity, and geographic distribution

Scientific Method

A five step process for empirical investigation of a hypothesis under conditions designed to control biases and subjective judgments

Significant Difference

Psychologists accept a difference between the groups as "real," when the probability that it might be due to an atypical sample drawn by chance is less than 5 in 100

Standard Deviation

A measure of variability that indicates the average difference between the scores and their mean

Survey

A quasi-experimental method in which questions are asked to subjects. When designing a survey, the researcher has to be careful that the questions are not skewed or biased toward a particular answer

Theory

A testable explanation for a set of facts or observations. In science, this is NOT just speculation or a guess