Between-Groups Design
Name 2 ways to randomize participants.
Use Excel function, RNG, blocking (Kazdin, 2003), every-other assignment, pulling names out of a hat
What are the 2 types of within-subjects design discussed in the chapter?
Crossover design and counterbalance crossover design (or Latin-square)
What is a strength OR weakness of posttest-only group design?
Strengths: high internal validity, closely reflects causality, pretest is unnecessary
Weaknesses: no pretest, limited external validity, need for simultaneous testing
A strength of WS design, in regards to experimental control, is that each individual subject is their own _________.
Control
DAILY DOUBLE!
Describe Type I and Type II errors using an example of your choice
Type I: You think it do, but it don't
Type II: You think it don't, but it do
What does a between-groups design do?
Compares different treatment-type groups against one another.
What is within-subjects design used for?
Comparing treatment types while using subjects as their own control
What is a strength of the pretest in a pretest-posttest between-groups design?
Decrease variability of the DV, help with selection, show individual patterns of score changes.
A strength of WS design is that the same statistical power can be achieved by using, in general, what percentage of the subjects that BG designs use?
50%
Poorly designed IVs threaten Kerlinger's _______ principle
MAXMINCON
List the 3 types of control groups
Waiting list, placebo, matched
The hallmark of WS designs minimizes error variance by doing what?
Using the subjects as their own control
What's 1 of the 2 strengths of a Solomon 4-group design?
Controls for sensitizing factors of the pretest by doing both the posttest-only and pre-post test designs OR
Inherently replicates the study to strengthen generalizability
Though the number of participants needed for a WS design may be fewer, an increase in what is still likely? Why?
Time,
Experimenters can't subject the same participants to the different treatment types at the same time.
What is a status variable?
All participant related variables that cannot be assigned
What are "Ob" and "Tx" shorthand for?
observation and treatment
What are 2 difficulties, stated within the reading, with a crossover design?
Sequencing effects, history effects, maturation, ordering effects
Name 2 of the 3 strengths of a factorial design
1) Allows investigation of two independent variables
2) Allows investigation of interaction between IVs
3) Reduces unexplained variance of the DV
How can a crossover design, intended to mitigate the sequencing effect, present a weakness for a practitioner?
The practitioner may want to know if one order had a stronger impact on the treatment than the other, even if they are both statistically significant.
Name the 2 of the 3 goals of manipulation checks
1) Conditions vary on the intended dimension
2) Conditions do not vary on other dimensions
3) Conditions are implemented in the intended fashion
DAILY DOUBLE!
What does Ob3C stand for?
Observation 3 from group C
In regards to treatment, what does counterbalance crossover treatment provide?
It allows experimenters to account for treatment order validity threats by changing the treatment order for different groups
What is the primary potential weaknesses of factorial designs?
Adding too many IVs resulting in losing the purpose of the study, having to code too many interactions, or losing statistical power
Explain cieling and floor effects.
The amount of change to the dependent variable my be limited in how much it can increase or decrease (due to retesting of the same individual multiple times).
After not paying attention in research Methods, your friend says, "Operationalizing variables is stupid!" What are 3 or 4 concerns would you have about his IV?
1) Determining the conditions or the level of the IV
2) Adequately reflecting the constructs designated as the cause in the research question
3) Limiting differences between conditions
4) Establishing the salience of differences between the conditions