Factorial Essentials Factorial design more than one IV IVs referred to as factors Identifying factorial designs Notation system Digits represent IVs Numerical values of digits represent the of levels of each IV ID: 642844
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Slide1
Chapter 5Factorial DesignsSlide2
Factorial Essentials
Factorial design = more than one IV
IVs referred to as “factors”
Identifying factorial designs
Notation system
Digits represent IVs
Numerical values of digits represent the # of levels of each IV
2x3 factorial (say: “two by three”)
2 IVs, one with 2 levels, one with 3 = 6 total conditions
2x4x4 factorial
3 IVs, with 2, 4, and 4 levels = 32 total conditionsSlide3
Factorial Essentials
Identifying factorial designs
Factorial matrix
2x2 (two levels each of type of
exam and presence of timer)
Timer No Timer
Math
Verbal
Presence of Timer
Exam TypeSlide4
Timer No Timer ½ Timer
Math
Verbal
Presence of Timer
Exam Type
This is a 2x3 design.
Timer No Timer
Math
Verbal
Music
Presence of Timer
Exam Type
This is a 3x2 design.Slide5
Timer
No Timer
5
5
Overall, is there an effect of
presence of timer?
I am interested to see whether performance on an exam is affected by projecting a countdown timer on the board during the test. Slide6
Timer
No Timer
5
10
Overall, is there an effect of
presence of timer?
I am interested to see whether performance on an exam is affected by projecting a countdown timer on the board during the test. Slide7
Timer
No Timer
Math
8
5
Verbal
2
5
Overall, is there an effect of
presence of timer?
Overall, is there an effect of
content type?
5
5
6.5
3.5
I am interested to see whether performance on an exam is affected by projecting a countdown timer on the board during the test. I also believe that the type of content on the exam affects exam score.Slide8
Overall, is there an effect of
presence of timer?
Overall, is there an effect of
content type?
Timer
No Timer
Math
6
4
Verbal
8
2
7
3
5
5
I am interested to see whether performance on an exam is affected by projecting a countdown timer on the board during the test. I also believe that the type
of content on the exam
affects exam score.Slide9
Overall, is there an effect of
presence of timer?
Overall, is there an effect of
content type?
Timer
No Timer
Math
5
5
Verbal
10
5
7.5
5
5
7.5
I am interested to see whether performance on an exam is affected by projecting a countdown timer on the board during the test. I also believe that the type of content on the exam affects exam score.Slide10
Timer
No Timer
Math
8
2
Verbal
2
8
Overall, is there an effect of
presence of timer?
Overall, is there an effect of
content type?
5
5
5
5
I am interested to see whether performance on an exam is affected by projecting a countdown timer on the board during the test. I also believe that the type of content on the exam affects exam score.Slide11
Timer
No Timer
Math
2
8
Verbal
2
8
Main effect of
presence of timer.
I am interested to see whether performance on an exam is affected by projecting a countdown timer on the board during the test. I also believe that the type of content on the exam affects exam score.Slide12
Timer
No Timer
Math
2
4
Verbal
4
6
Main effect of
presence of timer.
Main effect of
content type.
I am interested to see whether performance on an exam is affected by projecting a countdown timer on the board during the test. I also believe that the type of content on the exam affects exam score.Slide13
Timer
No Timer
Math
2
2
Verbal
4
4
Main effect of
content type.
I am interested to see whether performance on an exam is affected by projecting a countdown timer on the board during the test. I also believe that the type of content on the exam affects exam score.Slide14
Timer
No Timer
Math
8
2
Verbal
5
5
Main effect of
presence of timer.
Interaction effect.
I am interested to see whether performance on an exam is affected by projecting a countdown timer on the board during the test. I also believe that the type of content on the exam affects exam score.Slide15
Timer
No Timer
Math
8
2
Verbal
2
8
Interaction effect.
I am interested to see whether performance on an exam is affected by projecting a countdown timer on the board during the test. I also believe that the type of content on the exam affects exam score.Slide16
Timer
No Timer
Math
2
5
Verbal
8
5
Main effect of
content type.
Interaction effect.
I am interested to see whether performance on an exam is affected by projecting a countdown timer on the board during the test. I also believe that the type of content on the exam affects exam score.Slide17
Definition—Main Effects and Interactions
Main Effect
Overall effect of individual factors (IVs)
Interactions
When the effect
of one
factor (IV) depends on the level of the other factor (IV)For every 2-way ANOVA you conduct, you will always report TWO main effects and ONE interactionA) Main effect of IV1B) Main effect of IV2C) Interaction EffectSlide18
Reporting Results—Main Effects and Interactions
You must indicate which effects were significant and which were not.
Must include statement of statistical test in proper reporting format:
Test Letter (
df
)=Value, p
decisionMust include a statement (in words) explaining the effect. There is a significant main effect of presence of timer: F(1, 24) = 8.2, p<.05. Students taking an exam with a timer scored higher (M=8, SD=2) than students taking the exam without a timer (M=2, SD=2).Slide19
Reporting Results—Main Effects and Interactions
You must indicate which effects were significant and which were not.
Must include statement of statistical test in proper reporting format:
Test Letter (
df
)=Value, p
decisionMust include a statement (in words) explaining the effect. There is no significant main effect of exam type: F(1, 24) = 1.2, p=NS. Students taking an exam with a timer scored similarly (M=5, SD=2) to students taking the exam without a timer (M=5, SD=2).Slide20
Reporting Results—Main Effects and Interactions
You must indicate which effects were significant and which were not.
Must include statement of statistical test in proper reporting format:
Test Letter (
df
)=Value, p
decisionMust include a statement (in words) explaining the effect. There is a significant interaction effect of between exam type and presence of timer: F(1, 24) = 6.2, p<.05. Presence of timer improved performance for students taking the Math test, but did not have any effect on students taking the Verbal test.