a set of procedures used to gain information in the sciences; it involves systematic observations obtained in an objective manner that avoids biases by the observer or by the participants in the study
experiments need to be designed to be replicated
evaluation of creative work or performance by other people in the same field in order to maintain or enhance the quality
a possible answer to a research question. Scientific investigations are often designed to test a hypothesis
investigations in which two (or more) equivalent groups of subjects are treated in exactly the same way, except that the independent variable is different
an uncontrolled, extraneous variable or other flaw in the research design that yields alternative explanations for the results and thus limits the study's internal validity
A variable whose variation does not depend on that of another.
A variable whose value depends on that of another.
group within an investigation that does not receive the treatment being tested
a measurable characteristic of the participant such as height, weight, or gender that cannot be manipulated by a researcher.
hypotheses need to be falsifiable. capable of being falsified, counterfeited, or corrupted
between subjects design
each participant participates in one and only one group.
assigning participants to experimental conditions within an investigation in a manner such that each participant is equally likely to be assigned to each condition
a confound arising when there are no difference between the comparison groups within a study
confound arising when a behavior change is apparent after the introduction of an intervention, even though the intervention is known to be ineffectual
variables other than the independent variable that can affect the dependent variable
variable that is held constant or whose impact is removed in order to analyze the relationship between other variables without interference, or within subgroups of the control variable
the extent to which a study actually answers the research questions that it was designed to answer. A study with good internal validity has no confounds and only one explanation for the results
effect of the experimenter's expectations on the outcome of a study
procedure in which neither the experimenter nor the participants know to which condition the participants have been assigned
ceiling - situation in which the dependent variable yields scores at or near the top limit of the measurement tool for one or all of the conditions
floor - situation in which the dependent variable yields scores at or near the lower limit of the measurement tool for one or all conditions
measure of the degree of relationship between two variables. The strength of the relationship is represented by an absolute value
third variable/directionality problem
when two variables, A and B, are found to be positively or negatively correlated, it may be that changes in an unmeasured third variable, Variable C
within subjects design
design in which each participant receives each level of the independent variable at least once
a before–after design in which each participant is given the pretest, administered the treatment, then given the posttest.
when participants take the same test, etc. and have practice...therefore do better.
when participants become tired
experiments that happen over long periods of time. the time could have been the change, not the treatment.
regression to the mean
the phenomenon that extreme scores tend to be less extreme upon retesting; the move toward the mean
procedure for distributing the effect of an extraneous variable across the experimental conditions within a within-subjects design
a definition of the exact procedures used to produce a phenomenon or to measure some variable
consistency with which the same results are obtained from the same test, instrument, or procedure
extent to which the dependent variable is measuring what it purports to measure
confound arising when behavior difference in a study are caused by the participation of different experimenters
extent to which the results of an investigation can be generalized beyond the original study
the extent to which a measurement method accurately represents a construct and produces an observation distinct from that produced by a measure of another construct
all individuals to whom a research project is meant to generalize
subset of the population
sample in which the elements were selected randomly from a sampling frame
the prediction that there is no difference between the groups being compared. the null hypothesis is true if the population that the sample is from is the same as the population with which it is being compared
probability of making type I errors
type I error
rejecting the null hypothesis when it's ture
type II error
failing to reject the null hypothesis when it's false
probability of detecting a difference between the groups in the study when the null hypothesis is false. Power is calculated as 1-beta
p < .05, shows change is not due to chance
a statistical test done after (1) doing a general test such as an ANOVA and (2) finding asignificant effect. Post hoc tests are used to follow up on significant results obtained from a more general test. Because a significant ANOVA says only that at least two of the groups are significantly different from one another, post hoc tests may be performed to find out which groups are significantly different from one another.
procedures that organize, summarize, and describe a set of data
scores in a distribution that are inordinately large or small relative to the other scores
a statistic representing how closely two variables co-vary; it can vary from -1 (perfect negative correlation) through 0 (no correlation) to +1 (perfect positive correlation)
graphical representation of a correlation between to variables
procedures and measures used to make inferences about population characteristics from samples drawn from that population.
variation among scores that is not caused by the independent variable but instead is caused by random factors or by extraneous variables
between group variance
an estimate of the effect of the independent variable plus error variance
within group variance
estimate of the population error variance
analysis of variance, a statistical method in which the variation in a set of observations is divided into distinct components
independent samples t-test
used with a between subjects design
dependent samples t-test
used with a within subjects design
used with a correlational design
degrees of freedom
the number of observations that may freely vary; it is equal to the number of observations minus the number of restrictions placed on those observations
a functional relationship between an independent and dependent variable that is graphically represented by a curved line.
effect of observers on the behavior of subjects in the social sciences
The state of thinking or hoping that something, esp. something pleasant, will happen or be the case.
extent to which a sample does not represent the underlying population
INSTITUTIONAL REVIEW BOARDS - committees of individuals with diverse backgrounds who review proposals for research with human participants
nstitutional Animal Care and Use Committee (IACUC) is a self-regulating entity that, according to U.S. federal law, must be established by institutions that use laboratory animals for research or instructional purposes to oversee and evaluate all aspects of the institution's animal care and use program.
form given in advance to each participant in a research project; it describes the purpose of the study and what the participant will be asked to do and includes any known risks or benefits of the study
American Psychological Association - national organization of psychologists and people in related fields
secrecy about the identity of research participants
lying to, or misleading research participants
person with knowledge of the experiment posing as a participant
fully explaining the purpose of the experiment to the participants usually after the experiment is over
research design in which the effect of two or more independent variables on a dependent variable is assessed
an independent variable
effect of an independent variable on a dependent measure within a factorial design
average of scores for each level of an independent variable, disregarding other independent variables. marginal means are used in factorial designs to interpret main effects
in a factorial design, the effect of a dependent measure on an independent variable within each level of each independent variable
type of research design in which non equivalent groups are compared, a single group is observed a number of times, or both of these techniques are combined
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