42 terms

Chapter 2: Research Methods

Scientific Method
A five-step process for empirical investigation of a hypothesis under conditions designed to control biases and subjective judgments
Empirical Investigation
Approach to research that relies on sensory experience and observation as research data
Testable explanation for a set of facts or observations. In science, a theory is not just speculation or a guess
A statement predicting the outcome of a scientific study; a statement describing the relationship among variables of a study
Operational Definition
Specific descriptions of concepts involving the conditions of a scientific study; stated in terms of how the concepts are to be measured or what operations are being employed
Independent Variable
Stimulus condition so named because the experimenter changes it independently of all the other carefully controlled experimental conditions
Random Presentation
A process by which chance alone determines the order in which the stimulus is presented
Pieces of information. Information gathered by a researcher to be used in testing a hypothesis
Dependent Variable
The measure outcome of a study; the responses of the subjects in a study
Doing a study over to see whether the same results are obtained
Research in which the researcher controls all the conditions and directly manipulates the conditions, including the independent variable
Confounding/extraneous variables
Variables that have an unwanted influence on the outcome of an experiment
Constraints that the experimenter places on the experiment to ensure that each subject has the exact same conditions
Random Assignment
Each subject of the sample has an equal likelihood of being chosen for the experiment group of an experiment
Ex Post Facto
Research in which we choose subjects based on a pre-existing condition
Correlational Study
Type of research that is mainly statistical in nature. Determines the relationship between two variables
Quasi-experimental method in which questions are asked to subjects. Questions must not be skewed or biased
Naturalistic Observation
Research method in which subjects are observed in their natural environment
Longitudinal Study
Type of study in which one group of subjects is followed an observed for an extended period of time
Cross-Sectional Study
Study in which a representative cross-section of the population is tested or surveyed at one specific time
Cohort-Sequential Study
Research method in which a cross section of the population is chosen and then each cohort is followed for a short period of time
Personal Bias
Researcher allowing personal beliefs to affect the outcome of a study
Expectancy Bias
Researcher allowing his or her expectations to affect the outcome of a study
Double-Blind Study
Experimental procedure in which both researchers and participants are uninformed about the nature of the independent variable being administered
Institutional Review Board(IRB)
Committee at each institution where research is conducted to review every experiment for ethics and methodology
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
ABC'S of Laboratory Animal Research
All animal research must comply with ABC's of laboratory animal research; appropriate, beneficial, and caring
Frequency Distribution
Summary chart showing how frequently each of the various scores in a set of data occurs
Bar graph depicting a frequency distribution. The height of the bars indicates the frequency of a group of scores
Descriptive Statistics
Statistical procedures used to describe characteristics and responses of groups of subjects
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
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
Measure of central tendency for a distribution, represented by the score that occurs more often than any other
Simplest measure of variability represented by the difference between the highest and the lowest values in a frequency distribution
Standard Deviation
Measure of variability that indicates the average difference between the scores and their mean
Relationship between variables in which changes in one variable-- as in the correlation between a child's age and height
Normal Distribution
Bell-shaped curve, describing the spread of a characteristic throughout a population
Correlation Coefficient
Number between -1 and +1 expressing the degree of relationship between two variables
Inferential Statistics
Statistical techniques used to assess whether the results of a study are reliable or whether they might be simply the result of chance. Often used to determine whether two or more groups are essentially the same or different
Random Sample
Sample group of subjects selected by chance
Representative Sample
Sample obtained in a 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
Significant Difference
Psychologists accept difference between the groups as "real" or significant, when the probability that it might be to due to an atypical sample drawn by chance is less than 5 in 100