Designing Experiments Flashcards
<p>What is Experimental Design?</p>
<p>A plan of assigning experimental units to treatment conditions.</p>
What are the Three Statistical Design Principles?
- Control of effects of lurking variables
- Randomization–assigning individuals to treatments randomly by using random number table
- Replication
<p>Experimental Units</p>
<p>The individuals on which an experiment is done
| People=Subjects</p>
<p>Treatment</p>
<p>The specific experimental condition applied</p>
<p>Causation allows \_\_\_\_\_?</p>
<p>The experimenter to make inferences about the relationship between independent variables and dependent variables.</p>
<p>Controls allows \_\_\_\_\_\_?</p>
<p>The experimenter to eliminate confounding effects of lurking variables.</p>
<p>What does Variability do?</p>
<p>Makes it easier to detect differences in the treatment outcomes.</p>
<p>What is a Completely Randomized Design? </p>
<p>Participants are randomly assigned to treatments.</p>
<p>What is a Block Design?</p>
<p>This divides the participants into groups called blocks. Participants within each block are then randomly assigned treatments.</p>
<p>What is a Matched Pairs Design?</p>
<p>A type of block design used when an experiment only has two treatments and participants can be grouped into pairs based on a variable. Within these pairs, participants are randomly assigned to treatments. </p>
Practice Problem:
Which of the following statements are true?
- a completely randomized design offers no control for lurking variables.
- a randomized block design controls for the placebo effect.
- in a matched pairs design, participants within each pair receive the same treatment.
(A) 1 only (B) 2 only (C) 3 only (D) all of the above (E) none of the above
(E), none of the above, is the correct answer.
In a completely randomized design, experimental units are randomly assigned to treatment conditions which provides control for lurking variables.
To control for the placebo effect, a placebo must be included as a treatment option.
In a matched pairs design, experimental units within each pair are assigned to different treatments.
<p>Which design type is this an example of?<img></img></p>
<p>Block Design</p>
<p>Which design is this an example of?<img></img></p>
<p>Completely Randomized Design</p>
<p>Why is this an example of matched pairs design?</p>
<p><img></img></p>
<p>The participants are matched by type of car.</p>
Factor
Explanatory variable (Most experiments have multiple factors. When a treatment is formed from these factors, it is often called a level.)
Subject
Unit is a person
Placebo effect
Dummy treatment that has no physical effect
Double blind
Control group has no treatment or has been given a placebo.
Block
group of experimental units or subjects that are similar in ways that are expected to affect the response to the treatments
Comparative Experiment
Treatment–Observation
Observation 1–Treatment–Observation 2
