Chapter 10 Flashcards
(28 cards)
a variable that is controlled, such as when the researchers assign participants to a particular level (value) of the variable
manipulated variable
take the form of records of behavior or attitudes, such as self-reports, behavioral observations, or physiological measures
measured variables
any variable that a researcher holds constant on purpose
control variable
group in an experiment whose levels on the independent variable differ from those of the remaining group in some intended and meaningful way
comparison group
a level of an independent variable that is intended to represent “no treatment” or neutral condition
control group
when the control group is exposed to an inert treatment (such as a sugar pill)
placebo group
when a study has a control group, the other level(s) of the independent variable are called…
treatment group(s)
potential threats to internal validity
confounds
an experimenter’s mistake in designing the independent variable
design confound
a description of when the levels of a variable coincide in some predictable way with experimental group membership, creating a potential confound
systematic variability
a description of when the levels of a variable fluctuate independently of experimental group membership, contributing to variability w/in groups
unsystematic variability
when the kinds of participants in one level of the independent variable are systematically different from those in the other
selection effects
different groups of participants are placed into different levels of the independent variable
independent-groups design
there is only one group of participants, and each person is presented with all levels of the independent variable
within-groups design
participants are randomly assigned to independent variable groups and are tested on the dependent variable once
posttest-only design
participants are randomly assigned to at least two different groups and are tested on the key dependent variable twice (once before and once after exposure to the independent variable)
pretest/posttest design
a type of within-groups design in which participants are measured on a dependent variable more than once, after exposure to each level of the independent variable
repeated-measures design
participants are exposed to all the levels of an independent variable at roughly the same time, and a single attitudinal or behavioral preference is the dependent variable
concurrent-measures design
the probability that a study will show a statistically significant result when an independent variable truly has an effect in the population
power
when being exposed to one condition changes how participants react to the other condition
order effects
a long sequence might lead participants to get better at the task, or to get tired/bored toward the end
practice effects
some form of contamination carries over from one condition to the next
carryover effects
when researchers present the levels of the independent variable to participants in different sequences
counterbalancing
when a within-groups experiment has only 2-3 levels of an independent variable; all possible condition orders are represented
full counterbalancing
