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Research Methods #2

Terms in this set (193)

experimental design
the general plan for selecting participants, assigning participants to experimental conditions, controlling extraneous variables, and gathering data
principle of parsimony
the belief that explanations of phenomena and events should remain simple until the simple explanations are no longer valid
IV
a stimulus or aspect of the environment that the experimenter directly manipulates to determine its influences on behavior
DV
a response or behavior that the experimenter measures. Changes in the DV should be caused by manipulation of the IV
extraneous variables
uncontrolled variables that may unintentionally influence the dependent variable (DV) and thus invalidate the experiment
levels
differing amounts or types of an IV used in an experiment (also known as treatment conditions)
experimental group
in a two-group design, the group of participants that receives the IV
control group
in a two-group design, the group of participants that does not receive the IV
random assignment
a method of assigning research participants to groups so that each participant has an equal change of being in any group
random selection
a control technique that ensures that each member of the population has an equal chance of being chosen for an experiment
independent groups
groups of participants formed by random assignment
between-subjects comparison
refers to a contrast between groups of participants who were randomly assigned to groups.
confounded experiment
an experiment in which an extraneous variable varies systematically with the IV, which makes drawing a cause-and-effect relation impossible
correlated assignment (matched or paired assignment)
a method of assigning research participants to groups so that there is a relationship between small numbers of participants; these small groups are then randomly assigned to treatment conditions (also known as paired or matched assignment)
matched pairs
research participants in a two-group design who are measured and equated on some variable before the experiment
repeated measures
an experimental procedure in which research participants are tested or measured more than once
natural pairs
research participants in a two-group design who are naturally related in some way (e.g. a biological or social relationship). Usually twins
within-subjects comparison
refers to a contrast between groups of participants who were assigned to groups through matched pairs, natural paris, or repeated measures
internal validity
a type of evaluation of your experiment; it asks whether you IV is the only possible explanation of the results shown for your DV
history
a threat to internal validity; refers to events that occur between the DV measurements in a repeated-measures design
maturation
a threat to internal validity; refers to changes in participants that occur over time during an experiment; could include actual physical maturation or tiredness, boredom, hunger, and so on
testing
a threat to internal validity that occurs because measuring the DV causes a change in the DV
practice effect
a beneficial effect on a DV measurement caused by previous experience with the DV
reactive measures
DV measurements that actually change the DV being measured
nonreactive measures
DV measurements that do not influence the DV being measured
instrumentation (instrument decay)
a threat to internal validity that occurs if the equipment or human measuring the DV changes the measuring criterion over time
statistical regression
a threat to internal validity that occurs when low soccer's improve or high scorers fall on a second administration of a test solely as a result of statistical reasons
selection
a threat to internal validity that can occur if participants are chosen in such a way that the groups are not equal before the experiment; the researcher cannot then be certain that the IV caused any difference observed after the experiment
mortality
a threat to internal validity that can occur if experimental participants from different groups drop out of the experiment at different rates
interactions with selection
threats to internal validity that can occur if there are systematic differences between or among selected treatment groups based on maturation, history, or instrumentation
diffusion or imitation of treatment
a threat to internal validity that can occur if participants in one treatment group become familiar with the treatment of another group and copy that treatment
external validity
a type of evaluation of an experiment; do the experimental results apply to population and situations that are different from those of the experiment?
generalization
applying the results from an experiment to a different situation or population
population generalization
applying the results fro man experiment to a group of participants that is different and more encompassing than those used in the original experiment
environmental generalization
applying the results from an experiment to a situation or environment that differs from that of the original experiment
temporal generalization
applying the results from an experiment to a time that is different from the time when the original experiment was conducted
interaction of testing and treatment
a threat to external validity that occurs when a pretest sensitizes participants to the treatment yet to come
interaction of selection and treatment
a threat to external validity that can occur when na treatment effect is found only for a specific sample of participants
reactive arrangements
a threat to external validity caused by an experimental situation that alters participants' behavior, regardless of the IV involved
demand characteristics
features of the experiment that inadvertently lead participants to respond in a particular manner
multiple-treatment interference
a threat to external validity that occurs when a set of findings results only when participants experience multiple treatments in the same experiments
comparative psychology
the study of behavior in difference species, including humans
convenience sampling
a researcher's sampling of participants based on ease of locating the participants; often it does not involve true random selection
replication
an additional scientific study that is conducted in exactly the same manner as the original research project
replication with extension
an experiment that seeks to confirm (replicate) a previous finding but does so in a different setting or with different participants or under different conditions
between-groups variability
variability in DV scores that is due to the effects of the IV
error variability
Variability in DV scores that is due to factors other than the IV, such as individual differences measurement error, and extraneous variation (also known as within-groups variability)
statistics general formula
statistic = between-groups variability/error variability
degrees of freedom
the ability of a number in a specified set to assume any number
true experiment
An experiment in which the experimenter directly manipulates the IV
ex post facto research
a research approach in which the experimenter cannot directly manipulate the IV but can only classify, categorize, or measure the IV because it is predetermined in the participants (e.g. IV=sex)
experimental deseign
the general plan for selecting participants, assigning participants to experimental conditions, controlling extraneous variables, and gathering data
independent variable (IV)
a stimulus or aspect of the environment that the experimenter directly manipulates to determine its influence on behavior
principle of parsimony
the belief that explanations of phenomena and events should remain simple until the simple explanations are no longer valid
levels
differing amounts or types of an IV used in an experiment (also known as treatment conditions)
treatment groups
groups of participants that receive the IV
independent groups
groups of participants formed by random assignment
correlated groups
groups of participants formed by matching, natural pairs, or repeated measures
random assignment
a method of assigning research participants to groups os that each participant has an equal chance of being in any group
control procedure
one of the several steps experiments take to ensure that potential extraneous variables are controlled, including random assignment, matching, and so on
confounded experiment
an experiment in which an extraneous variable varies systematically with the IV, which amens drawing a cause-and-effect relation impossible
matching variable
a potential extraneous variable on which we measure our research participants and from which we form sets of participants who are equal on the variable
placebo effect
an experimental effect caused by expectation or suggestion rather than the IV
one-way ANOVA
a statistical test used to analyze data from an experimental design with one independent variable that has three or more groups (levels)
completely randomized ANOVA
this one-way ANOVA uses independent groups or participants
repeated-measures ANOVA
this one-way ANOVA uses correlated groups of participants
operational definition
defining the independent, dependent, and extraneous variables in terms of the operations needed to produce them
sum of squares
the amount of variability in the DV attributable to each source
source table
a table that contains the results of ANOVA. Source refers to the source of the different types of variation
mean square
the "averaged" variability for each source; computed by dividing each source's sum of squares by its degrees of freedom
variance
a single number that represents the total amount of variation in a distribution; also the square of the standard deviation
post hoc comparisons
statistical comparisons made between group means after finding a significant F ratio
asymptotic
refers to tails of distributions that approach the baseline but never touch the baseline
factorial design
an experimental design with more than one IV
main effects
refers to the sole effect of one IV in a factorial design
interaction
the joint, simultaneous effect on the DV of more than one IV
correlated groups
groups of participants formed by matching, natural pairs, or repeated measures
mixed assignment
a factorial design that has a mixture of independent groups for one IV and correlated groups for another IV. In larger factorial designs at least one IV has independent groups and at least one has correlated groups (also known as mixed groups)
ex post facto research
a research approach in which the experimenter cannot directly manipulate the IV but can only classify, categorize, or measure the IV because it is predetermined in the participants (e.g., IV=sex)
three-way design
a factorial design with three IVs
treatment variability
variability in DV scores due to the effects of the IV (also known as between-group variability)
error variability
variability in DV scores due to factors other than the IV, such as individual differences, measurement error, and extraneous variation (also known as within-groups variability)
synergistic effects
dramatic consequences that occur when you combine two or more substances, conditions, or organisms. The effects are greater (or less) than what is individually possible
marginal significance
refers to statistical results with a probability of chance between 5% and 10%; in other words, almost significant, but not quite. Researchers often talk about such results as if they reached the p=.05 level
Type I Error
accepting the experimental hypothesis when the null hypothesis is true
internal validity
a type of evaluation of your experiment; it asks whether your IV is the only possible explanation of the results shown for your DV
confounding
caused by an uncontrolled extraneous variable that varies systematically with the IV
extraneous variables
uncontrolled variables that may unintentionally influence the dependent variable (DV) and thus invalidate an experiment
cause-and-effect relation
occurs when we know that a particular IV (cause) leads to specific changes in a DV (effect)
random assignment
this control technique ensures that each participant has an equal chance of being assigned to any group in an experiment
random selection
a control technique that ensures that each member of the population has an equal chance of being chosen for an experiment
selection
a threat to internal validity that can occur if participants are chosen in such a way that the groups are not equal before the experiment; the researcher cannot then be certain that the IV caused any difference observed after the experiment
history
a threat to internal validity; refers to events that occur between the DV measurements in a repeated-measures design
maturation
an internal validity threat; refers to changes in participants that occur over time during an experiment; could include actual physical maturation or tiredness, boredom, hunger, and so on
testing
a threat to internal validity that occurs because measuring the DV causes a change in the DV
statistical regression
this threat to internal validity occurs when low scores improve or high scorers fall on a second administration of a test solely as a result of statistical reasons
interactions with selection
these threats to internal validity can occur if there are systematic differences between or among selected treatment groups based on maturation, history, or instrumentation
experimental mortality
this that to internal validity can occur if experimental participatns from different groups drop out of the experiment at different rates
instrumentation
this threat to internal validity occurs i the equipment or human measuring the DV changes its measuring criterion over time
diffusion or imitation of treatment
this threat to internal validity can occur if participants in one treatment group become familiar with the treatment being received by another group and copy that treatment
single-case experimental design
an experiment that consists of one participant (also known as N=1designs)
case-study approach
an observational technique in which a record of observations about a single participant is compiled
experimental analysis of behavior
a research approach popularized by B.F. Skinner, in which a single participant is studied
baseline
a measurement of a behavior made under normal conditions (i.e. no IV is present); a control condition. Recommended that you collect at least three observations during the baseline period in order to establish a trend in the data
A
refers to the baseline measurement in a single-case design
B
refers to the outcome (treatment) measurement in a single-case design
A-B design
a single-case design in which you measure the baseline behavior, institute a treatment, and use a post test. Poor for determining causality because many of the the internal threats to validity
A-B-A design
a single-case design consisting of a baseline measurement, a treatment, a posttest, and a return to the baseline condition. It may not be recommended if the participant is left without a beneficial or necessary treatment in the second baseline
A-B-A-B design
a single-case design consisting of a baseline treatment, posttest, return to baseline, repeated treatment,a nd second posttest. This design gies the best chance of isolating causation
quasi-experimental design
a research design used when the researcher cannot randomly assign experimental participants to the groups but the researcher does manipulate an IV and measure a DV
nonequivalent group design
a design involving two or more groups that are not randomly assigned; a comparison group (no treatment) is compared to one or more treatment groups
interrupted time-series design
a quasi-experimental design, involving a single group of participants, that includes repeated pretreatment measures, an applied treatment, and repeated post treatment measures
qualitative research
research conducted in a natural setting that seeks to understand a complex human behavior by developing a complete narrative description of that behavior
confirmability
the extent to which the qualitative research report is accurate, unbiased, and can be confirmed by others
dependability
the extent to which the researcher believes that the same results would be produced in the study were replicated
credibility
the accuracy of the identification and description of the subject of the study
transferability (generalizability)
the extent to which the results of a qualitative research project can eb generalized to other settings and groups
naturalistic observation
seeking answers to research questions by observing behavior in the real world
ethnographic inquirty
research in which the goal is to learn about a culture or some aspect of a culture from the perspective of the members of that culture
participant observation
research in which the researcher becomes part of the group being studied
focus group
seven to 10 participants with shared experiences or similar characteristics who meet for 1 to 1 1/2 hours to discuss a topic of common interest
narrative study
researchers actively gather and interpret stories that individuals in their target group use to describe their lives
case studies
studies involving the intensive observation of a single participant over an extended period of time
artifact analysis
involves the examination and analysis of extant artifacts, such as text-based materials
historiography
the collection and analysis of information and data in order to reconstruct past events
symbolic interaction
study of the common symbols that give meaning to human interaction within a social group context
grounded-theory
a qualitative research approach that attempts to develop theories of understanding based on data from the real world
open coding
the process of describing data through means such as examination, comparison, conceptualization, and categorization
axial coding
the process of rearranging data after open coding so that new relations are formed between concepts
selective coding
the process of selecting the main phenomenon (core category) around which all other phenomena (subsidiary categories) are grouped, arranging the groupings, studying the results, and rearranging where necessary
process
the manner in which actions and interactions occur in a sequence or theory
transactional system
an analysis of how action and interactions relate to their conditions and consequences
conditional matrix
a diagram that helps the researcher reconsider the conditions and consequences related to the phenomenon under the study
descriptive research methods
research methods that do not involve the manipulation of any variable by the researcher
naturalistic observation
seeking answers to research questions by observing behavior in the real world
reactance or reactivity effect
the finding that participants respond differently when they know they are being observed
Hawthorne effect
another name for reactance or reactivity effect.
time sampling
making observations at different time periods
situation sampling
observing the same behavior in different situations
interobserver reliability
the extent to which observers agree
percentage of agreement calculation
(number of times observers agree/ number of opportunities to agree) x 100
correlational study
determination of the relation between two variables
positive correlation
as scores on one variable increase, scores on the second variable also increase
negative correlation
as scores on one variable increase, scores on the second variable decrease
zero correlation
two variables under consideration are not related
ex post factor studies
a study in which the variable(s) to be studied are selected after they have occurred
descriptive survey
seeks to determine te percentage of the population that has a certain characteristic, holds a particular opinion, or engages in a particular behavior
analytic survey
seeks to determine the relevant variables and how they are related
pilot testing
preliminary, exploratory testing that is done prior to the complete research project
demographic data
information about participants' characteristics such as age, sex, income, and academic major
validity
the extent to which a test or inventory measures what is is supposed to measure
content validity
the extent to which test items actually represent the type f material they are supposed to represent
interrator reliability
degree of agreement among judges concerning the content validity of test or inventory items
concurrent validity
degree to which the score on a test of inventory corresponds with another measure of the designated trait
criterion validity
established by comparing the score on a test or inventory with a future score on another test or inventory
reliability
extent to which a test or inventory is consistent in its evaluation of the same individuals
test-retest procedure
determination of reliability by repeatedly administering a test to the same participants
split-half technique
determination of reliability by dividing the test or inventory into two subtests and the comparing the scores made on the two halves
achèvement test
designed to evaluate and individual's level of mastery or competence
aptitude test
designed to assess and individual's potential ability or skill in a particular job
personality test or inventory
measures a specific aspect of the individual's motivational state, interpersonal capability, or personality
population
the complete set of individuals or events
sample
a group that is selected to represent the population
random sample
a sample in which every member of the population has na equal likelihood of being included
random sampling without replacement
once chosen, a score, event, or participant cannot be returned to the population to be selected again
random sampling with replacement
once chosen, a score, event, or participant can be returned to the population to be selected again
stratified random sampling
random samples are drawn from specific subpopulations or strata of the general population
single-strata approach
gathering data from a single stratum of the population of interest
cross-sectional research
comparison of two or more groups during the same, rather limited, time period
longitudinal research project
obtaining research data from the same group of participants over an extended period of time
cohort
a group of individuals born during the same time period
internal validity
a type of evaluation of your experiment; it asks whether your IV is the only possible explanation of the results shown for your DV
testing
a threat to internal validity that occurs because measuring the DV changes the DV
practice effect
a beneficial effect on a DV measurement caused by previous experience with the DV
reactive measures
DV measurements that actually change the DV being measured
nonreactive measures
DV measurement that do not influence the DV being measured
selection
a threat to internal validity that can occur if participants are chosen in such a way that the groups are not equal before the experiment; the researcher cannot then be certain that the IV caused any difference observed after the experiemtn
mortality
a threat to internal validity that can occur if experimental participants from different groups drop out of the experiment at different rates
diffusion or imitation o treatment
a threat to internal validity that can occur if participants in one treatment group ebce familiar with the treatment of another group and copy that treatment
external validity
a type of evaluation of an experiment; do the experimental results apply to the populations and situations that are different from those of the experiment?
generalization
applying the results from an experiment to a different situation or population
population generalization
applying the results from an experiment to a group of participants that is different and more encompassing than those used in the original experiment
environmental generalization
applying the realists from an experiment to a situation of environment that differs from that of the original experiment
temporal generalization
applying the results from an experiment to a time that is different from the time when the original experiment was conducted
interaction of testing and treatment
a threat to external validity that occurs when na pretest sensitizes participants to the treatment yet to come
interaction of selection and treatment
a threat to external validity that can occur when na treatment effect is found only for specific sample of participants
reactive arrangements
a threat to external validity caused by an experimental situation that alters participants' behavior, regardless of the IV involved
demand characteristics
features of the experiment that inadvertently lead participants to respond in a particular manner
multiple-treatment interference
a threat to external validity that occurs when a set of findings results only when participants experience multiple treatments in the same experiment
comparative psychology
the study of behavior in different species, including humans
convenience sampling
a researcher's sampling of participants based not he ease of locating the participants; often it does not involve true random selection
replication
an additional scientific study that is conducted in exactly the same manner as the original research project
replication with extension
an experiment that seeks to confirm (replicate) a previous finding but does so in a different setting or with different participants or under different conditions
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