PSYCH 302 FINAL EXAM QUESTIONS
AND ANSWERS
One-group pretest/posttest design - ANSWER-An experiment in which a researcher
recruits one group of participants; measures them on a pretest; exposes them to a
treatment, intervention, or change; and then measures them on a posttest.
maturation threat - ANSWER-Is a threat to internal validity that occurs when an
observed change in an experimental group could have emerged spontaneously over
time
history threat - ANSWER-Is a threat to internal validity that occurs when it is unclear
whether a change in the treatment group is caused by the treatment itself or by an
external or historical factor
regression to the mean threat - ANSWER-A phenomenon in which an extreme
finding is likely to be closer to its own typical, or mean, level the next time it is
measured, because the same combination of chance factors that made the finding
extreme are not present the second time
attrition threat - ANSWER-Is a threat to internal validity that occurs when a
systematic type of participant drops out of the study before it ends
testing threat - ANSWER-Is a kind of order effect in which scores change over time
just because participants have taken the test more than once; includes practice
effects
instrumentation threat - ANSWER-Is a threat to internal validity that occurs when a
measuring instrument changes over time
selection-attrition threat - ANSWER-Is a threat to internal validity in which
participants are likely to drop out of either the treatment group or the comparison
group, not both
observer bias - ANSWER-A bias that occurs when observer expectations influence
the interpretation of participant behaviors or the outcome of the study.
demand characteristics - ANSWER-A cue that leads participants to guess a study's
hypotheses or goals, a
threat to internal validity
double blind study - ANSWER-A study in which neither the participants nor the
researchers who evaluate them know who is in the treatment group and who is in the
comparison group
, masked (i.e. single-blind) design - ANSWER-A study design in which the observers
are unaware of the experimental conditions to which participants have been
assigned.
placebo effects - ANSWER-A response or effect that occurs when people receiving
an experimental treatment experience a change only because they believe they are
receiving a valid treatment.
Explain how comparison groups, double-blind studies, and other design choices can
help researchers avoid many of these threats to internal validity. - ANSWER-
Comparison groups, double-blind studies, and other design choices can help
researchers avoid many of these threats to internal validity because they protect the
observer and researcher remains unbiased
Explain why experiments are still useful despite all the potential threats to internal
validity. - ANSWER-Experiments are still useful despite all the potential threats to
internal validity because Internal validity makes the conclusions of a causal
relationship credible and trustworthy. Without high internal validity, an experiment
cannot demonstrate a causal link between two variables
Null effect - ANSWER-This is a finding that an independent variable did not make a
difference in the dependent variable; there is no significant covariance between the
two
Ceiling effect - ANSWER-an experimental design problem in which independent
variable groups score almost the same on a dependent variable, such that all scores
fall at the high end of their possible distribution
Floor effect - ANSWER-an experimental design problem in which independent
variable groups score almost the same on a dependent variable, such that all scores
fall at the low end of their possible distribution
Noise - ANSWER-Unsystematic variability among the members of a group in an
experiment, which might be caused by situation noise, individual differences, or
measurement error
Measurement error - ANSWER-The degree to which the recorded measure for a
participant on some variable differs from the true value of the variable for that
participant
Situation noise - ANSWER-unrelated events or distractions in the external
environment that create unsystematic variability within groups in an experiment
Describe at least two ways that a study might show inadequate variance between
groups, and indicate how researchers can identify such problems. - ANSWER-They
can identify ceiling or floor effects; they can measure better and make sure the
environment is carefully controlled. Bigger sample size, more representative
AND ANSWERS
One-group pretest/posttest design - ANSWER-An experiment in which a researcher
recruits one group of participants; measures them on a pretest; exposes them to a
treatment, intervention, or change; and then measures them on a posttest.
maturation threat - ANSWER-Is a threat to internal validity that occurs when an
observed change in an experimental group could have emerged spontaneously over
time
history threat - ANSWER-Is a threat to internal validity that occurs when it is unclear
whether a change in the treatment group is caused by the treatment itself or by an
external or historical factor
regression to the mean threat - ANSWER-A phenomenon in which an extreme
finding is likely to be closer to its own typical, or mean, level the next time it is
measured, because the same combination of chance factors that made the finding
extreme are not present the second time
attrition threat - ANSWER-Is a threat to internal validity that occurs when a
systematic type of participant drops out of the study before it ends
testing threat - ANSWER-Is a kind of order effect in which scores change over time
just because participants have taken the test more than once; includes practice
effects
instrumentation threat - ANSWER-Is a threat to internal validity that occurs when a
measuring instrument changes over time
selection-attrition threat - ANSWER-Is a threat to internal validity in which
participants are likely to drop out of either the treatment group or the comparison
group, not both
observer bias - ANSWER-A bias that occurs when observer expectations influence
the interpretation of participant behaviors or the outcome of the study.
demand characteristics - ANSWER-A cue that leads participants to guess a study's
hypotheses or goals, a
threat to internal validity
double blind study - ANSWER-A study in which neither the participants nor the
researchers who evaluate them know who is in the treatment group and who is in the
comparison group
, masked (i.e. single-blind) design - ANSWER-A study design in which the observers
are unaware of the experimental conditions to which participants have been
assigned.
placebo effects - ANSWER-A response or effect that occurs when people receiving
an experimental treatment experience a change only because they believe they are
receiving a valid treatment.
Explain how comparison groups, double-blind studies, and other design choices can
help researchers avoid many of these threats to internal validity. - ANSWER-
Comparison groups, double-blind studies, and other design choices can help
researchers avoid many of these threats to internal validity because they protect the
observer and researcher remains unbiased
Explain why experiments are still useful despite all the potential threats to internal
validity. - ANSWER-Experiments are still useful despite all the potential threats to
internal validity because Internal validity makes the conclusions of a causal
relationship credible and trustworthy. Without high internal validity, an experiment
cannot demonstrate a causal link between two variables
Null effect - ANSWER-This is a finding that an independent variable did not make a
difference in the dependent variable; there is no significant covariance between the
two
Ceiling effect - ANSWER-an experimental design problem in which independent
variable groups score almost the same on a dependent variable, such that all scores
fall at the high end of their possible distribution
Floor effect - ANSWER-an experimental design problem in which independent
variable groups score almost the same on a dependent variable, such that all scores
fall at the low end of their possible distribution
Noise - ANSWER-Unsystematic variability among the members of a group in an
experiment, which might be caused by situation noise, individual differences, or
measurement error
Measurement error - ANSWER-The degree to which the recorded measure for a
participant on some variable differs from the true value of the variable for that
participant
Situation noise - ANSWER-unrelated events or distractions in the external
environment that create unsystematic variability within groups in an experiment
Describe at least two ways that a study might show inadequate variance between
groups, and indicate how researchers can identify such problems. - ANSWER-They
can identify ceiling or floor effects; they can measure better and make sure the
environment is carefully controlled. Bigger sample size, more representative
