8.1 Experimental Design Flashcards
The simplest possible ____ ____ has two variables: the independent variable and the dependent variable.
experimental design
The independent variable has a minimum of two levels, an ____ group and a ____ group.
experimental, control
The experimental method involves control of ____ ____, through either keeping such variables constant or using randomisation to make sure that any extraneous variable will affect both groups equally.
extraneous variables
A researcher using a ____-____ design must obtain two equivalent groups of participants, introduce the independent variable, and measure the effect of the independent variable on the dependent variable.
posttest-only
In a posttest-only design the procedures used must achieve equivalent groups to eliminate any potential ____ ____: the people selected to be in the conditions cannot differ in any systematic way.
selection differences
In the posttest-only design the researcher must choose ___ ___ of the independent variable, such as an experimental group that receives treatment and a control group that does not.
two levels
In the posttest-only design, the effect of the independent variable is ____. The same measurement procedure is used for both groups, so that the comparison of the two groups is possible.
measured
In a ____ -____ design a pretest is given before experimental manipulation is introduced.
pretest-posttest
The pretest-posttest design makes it possible to ascertain that the groups were, in fact, ____ at the beginning of the experiment.
equivalent
With a sufficiently large sample of participants, ____ ____ will produce groups that are virtually identical in all respects.
random assignment
A pre-test enables the researcher to assess whether the groups are in fact ____ to begin with.
equivalent
Sometimes, a pretest is ____ to select the participants in the experiment.
necessary
A pre-test is also necessary whenever there is a possibility that participants will drop out of the experiment; this is most likely to occur in a study that lasts over a long period of time. The dropout factor in experiments is called ____ or ____.
attrition or mortality
Use of a pre-test enables you to asses the effects of ____; you can look at the pre-test scores of the dropouts and know whether their scores differ from the scores of the individuals completing the study.
attrition
One disadvantage of a pre-test, however, is that it may be ____-____ and awkward to administer in the context of the particular experimental procedures being used.
time-consuming
Perhaps most important, the pretest can ____ participants to what you’re studying, enabling them to figure out your hypothesis.
sensitise
An ____ ____ design is where participants are randomly assigned to the various conditions so that each participates in only one group. A.k.a. between-subjects design.
independent groups
In an experiment with two conditions, for example, each participant is assigned to both levels of the independent variable, called a ____ ____ design. Each participant is measured after receiving each level of independent variable. A.k.a. within-subjects design.
repeated measures
In an independent groups design, different participants are assigned to each of the conditions using ____ ____.
random assignment
In a repeated measures design, the same individuals will participate in ____ conditions.
both
The repeated measures design has several advantages. An obvious one is that ____ research participants are needed, because each individual will participate in all conditions.
fewer
An additional advantage of repeated measures designs is that they are extremely sensitive to finding ____ ____ ____ between groups. This is because we have data from the same people in both conditions.
statistically significant differences
The major problem with the repeated measures design stems from the fact that the different conditions must be presented in a particular ____.
sequence
The order of presenting the treatments can affect the dependent variable, this is called an ____ ____.
order effect
Performance on a second task might improve merely because of the practice gained on the first task. This improvement is called a ____ ____, learning effect.
practice effect
A deterioration in performance from the first to the second condition as the research participant becomes tired, bored, or distracted, is called a ____ ____.
fatigue effect
It is also possible for the effect of the first treatment to carry over to influence the response to the second treatment, this is known as a ____ ____.
carryover effect
There are two approaches to dealing with order effects. The first is to employ ____ techniques. The second is to devise a procedure with sufficient ____ between conditions.
counterbalancing, intervals
With complete ____, all possible orders of presentation of the measures are included in the experiment.
counterbalancing
A technique to control for order effects without having all possible orders is to construct a ____ ____.
Latin Square
A latin square is a ___ __ of ____ constructed to ensure that (1) each condition appears at each ordinal position and (2) each condition precedes and follows each condition one time.
limited set of orders
Using a Latin square to determine order controls for most ____ ____ without having to include all possible orders.
order effects
Instead of simply randomly assigning participants to groups, in the ____ ____ design, the goal is to first match people on a particular variable.
matched pairs
In the matched pairs design the matching variable will be either the ____ ____ or a variable that is strongly related to the dependent variable.
dependent measure
When using a matched pairs design, the first step is to obtain a measure of the matching variable from each ____ . The participants are then rank ordered from highest to lowest based on the scores on the matching variable.
individual
Researchers can form matched pairs that are approximately ____ on the characteristic (the highest two participants form the first pair, the next two form the second pair, and so on).
equal
Finally, in the matched pairs design, the members of each pair are ____ assigned to the conditions in the experiment.
randomly
A matched pairs design ensures that the groups are equivalent (on the matching variable) prior to introduction of the ____ ____ manipulation.
independent variable
