Class 3 Between Group Designs, Expo Facto Designs, Status Variable Chapters HWK 7 (146-163),10 (224-...
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Transcript of Class 3 Between Group Designs, Expo Facto Designs, Status Variable Chapters HWK 7 (146-163),10 (224-...
Class 3Between Group Designs, Expo Facto Designs, Status Variable
Chapters HWK 7 (146-163),10 (224-233, 243-4) 12(308) ANOVA PDF
Between Group Design
Therapy Outcome Research PurposeIndependent VariableAssignment to GroupsTreatment DeliveryParticipant SelectionControl Group
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Between Group DesignTherapy Outcome Research Purpose Compare treatment groups
under tightly controlled conditions
Independent Variable Highly specified; manipulated; categorical
Assignment to Groups Random; stratified; each participant only 1 treatment
Treatment Delivery Closely monitored
Participants Highly selective
Control Group No-treatment/Placebo, orOther Active Treatment 3
Within Group Design Therapy Outcome Research Purpose Compare treatments under
tightly controlled conditions
Independent Variable Highly specified; manipulated; categorical
Assignment to Groups Random to the time each treatment is delivered; each participant all treatments
Treatment Delivery Closely monitored
Participants Highly selective
Control Group Active Treatments 4
Does loud noises affect short term memory? – Within Subjects Variable
.5
Advantages of Pre-Test
Select participants; describe groups Use as a covariate when comparing post-
test means Comparing gain scoresis not recommended
(p.153) Compare drop-outs and completers in initial
severity Use as post-test for early terminators in
“intent to treat” analyses 6
Treatment Study: Question 5 Research Design
Independent Variables
Dependent Variables
Participants
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Treatment Study: Question 5 Research Design
Experimental, BW-groups, posttest, factorial
Independent Variables (Main Effects)
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Treatment Study: Question 5 Research Design
Experimental, BW-groups, posttest, factorial
Independent Variables (Main Effects) Treatments: Cult. Infused vs. Standard Therapist Ethnicity: Latino/a vs. White
In this study, is ethnicity a true IV or a status variable? Why?
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Study Description
A study examined the effectiveness of two treatments (culturally infused treatment vs. treatment as usual) to enhance the parenting skills of 100 mothers of Mexican descent of a 12-14 age child.
The treatments were delivered by either a Latino therapist (half of the sample) or a White therapist (to the other half).
Parents were randomly assigned to the type of treatment and the therapist’s ethnicity conditions.
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Treatment Study: Question 5 Dependent Variable(s)
Scores Parenting Skills – Continuous
Participants 100 Moms of Mexican descent With a child 12-14 years old
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Treatment Study: Question 5(b) Potential research questions regarding
treatment effectiveness
Question 1:
Question 2:
Question 3:
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Treatment Study: Question 5(b) Potential research questions regarding
treatment effectiveness
Question 1:Main Effect Treatment Group
Question 2:Main Effect Therapist Ethnicity
Question 3: Moderation Effect Treatment X Therapist
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Question 1 Do parents in the Culturally Infused
Treatment (T1) obtain higher post-test scores in parenting skills than parents in the Treatment as Usual (T2) ?
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Treatment 1 Treatment 2Mean = 7.9 Mean = 5.2
Question 2 Do parents who had a Latino Therapist
obtain higher post-test scores in parenting skills than parents who had a White Therapist
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Latina/o Th Anglo ThMean = 6.5 Mean = 6.4
Question 3 Moderation Does Therapist ethnicity moderate the
association of type of treatment to parenting skills scores? Among participants with Latino/a TH: Among participants with Anglo TH:
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Treatment 1Infused
Treatment 2Usual
Latina/o Anglo
2X2 ANOVA with ModerationCovariate Pre-Test Parenting ScaleModerator: Therapist Ethnicity
IVsDV
Post Test Parental Skills Scales
F statistic
Treatment 2 Means Treat. I vs. Treat 2
Main Effect *
Therapist Ethnicity
2 Means Anglo vs. Latino/a Th
Main Effect ns
Treatment X Therapist Ethnicity
4 MeansTh Anglo: T1 vs. T2Th Hispanic: T1 vs. T2
Interaction Effect
? 17
Question 3 Moderation Does Therapist ethnicity moderate the
association of type of treatment to parenting skills scores? Among participants with Latino/a TH: do parents in
T1 obtain higher parenting scores than those in T2 Among participants with Anglo TH: do parents in
T1 obtain higher parenting scores than those in T2
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Treatment 1Infused
Treatment 2Usual
Latina/o Mean = 7.4* Mean = 6.1Anglo Mean = 7.0* Mean = 6.4
2X2 ANOVA with ModerationDV Post-Test Parenting ScaleCovariate Pre-Test Parenting Scale
IVDV
Post Test Parental Skills Scales
F statistic
Treatment 2 Means Treat. I* vs. Treat 2
Main Effect *
Therapist Ethnicity
2 Means Anglo vs. Latino/a Th
Main Effect ns
Treatment X Therapist Ethnicity
4 MeansTh Anglo: T1* vs. T2Th Hispanic: T1* vs. T2
Interaction Effect ns
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Table 1 Main Effects Means Post-Test Parenting Scale
Effects Post-Test Parenting Scale
Mean Mean F value
Main: Treatment
Infused Treatm.7.9*
Usual Treatm.6.2
*p<.05
Main Therapist Ethnicity
Hispanic Th.6.5
Anglo Th.6.4
NS
InteractionTreat X Th Eth
Infused TreatLatino/a 7.4*Anglo 7.0*
Infused Treat6.16.0
NS
Possible range of scores for parenting Scale = 1 to 10 20
Results showed A main effect for treatment
No main effect for therapist
Therapist ethnicity did not moderate the effect of treatment on parenting skills for the White therapists, Infused T>Usual T for Latino/a therapists, Infused T>Usual T
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Does Therapist Ethnicity moderate the treatment difference in parental skills? ??
1.Does the culturally infused vs. the usual treatment produce a higher mean score in mom’s post-test parenting skills when administered by the Anglo Therapists? Yes - 7.0 vs. 6.4 *p <.05
lDoes the culturally infused vs. the usual treatment produce a higher mean score in mom’s post-test parenting skills when administered by the Latina/o Therapists Yes – 7.4 vs. 6.1 *p <.05
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Does Therapist Ethnicity moderate the treatment difference in parental skills?
NOTherapists’ ethnicity did not matter: with both types of therapists, mothers in culturally infused treatment obtained higher post-test parental skills scores than mothers in usual treatment.
23
Conclusion If interaction effect(s) is present, related
main effect(s) is (are) not interpreted.
In this case, should we interpret the treatment main effect?
24
Conclusion If interaction effect(s) is present, related
main effect(s) is (are) not interpreted.
In this case, should we interpret the treatment main effect?Yes, because there is no moderation effect for Therapist ethnicity
25
Table 1A Main & Interaction Effects Means Post-Test Parenting Scale
Effects Post-Test Parenting Scale
Mean Mean F value
Main: Treatment
Infused Treatm.7.9*
Usual Treatm.6.2
*p<.05
Main Therapist Ethnicity
Hispanic Th.6.5
Anglo Th.6.4
NS
InteractionTreat X Th Eth
Infused TreatLatino/a 7.4ns
Anglo 7.0*
Usual Treat7.36.0
*p<.05
Possible range of scores for parenting Scale = 1 to 10 26
Conclusion Regarding Table 1A, should we interpret
the treatment main effect? NO, because there is a moderation effect for Therapist ethnicity
Results show that for Latino Th – no effect for treatment typeFor Anglo Th- Infused T >Usual T
27
Second Study Question 6
Research Design
Independent Variables
Dependent Variables
Participants
28
Second Study Question 6
Research Design Non-experimental - Association Factorial Between Groups
29
Second Study Q. 6
Independent Variables Moms Place of Birth Target Child’s Gender• US• Mexico
• Boys• Girl
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Participants• 100 Mothers •100 12-14 year olds
•50 daughters•50 sons
Dependent Variables• Self Reported Parenting Skills Scale -- SRPSS
Research QuestionsDV- SR Parenting Scale #6
Main Effects
DV- Pre-test SR Parental Skills Scale F statistic
Main Effect
Main Effect
Moderation effects
31
Research QuestionsDV- SR Parenting Scale #6
Main EffectsDV- Pre-test
SR Parental Skills Scale F statistic
Mom Place of Birth
Mexico vs. US(Mexico + USA)
Main Effect
Child Gender Boys vs. Girls(Boys + Girls)
Main Effect
Which we want to
examine as moderator? 32
Research Questions Study Question # 61. Main Effect Place of birth: Do moms born in
USA obtain higher scores in pre-test parenting skills than moms born in Mexico?
2. Main Effect Child’s Gender: Do moms of boys obtain higher scores in pre-test parenting skills than moms of girls?
3. Interaction Effect: Moderator??
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Main Effects Q. 6C-1 & 6C-2 Place of Birth:
It is hypothesized that:
Target Child’s Gender It is hypothesized that:
34
Main Effects Place of Birth: (acculturation)
It is hypothesized that mothers born in the US will obtain higher mean score in the parenting skills measure than mothers born in Mexico
Child’s Gender (gender role rearing beliefs) It is hypothesized that mothers of boys will
obtain a higher mean score in the parenting skills measure than mothers of girls
35
Table 4: 2X2 ANOVA Main EffectsModerator: Mom P Birth
IVsDV- Pre-test
SR Parental Skills Scale F statistic
Mom Place of Birth
Mexico vs. US(Mexico + USA)
Main Effect
Child Gender Boys vs. Girls(Boys + Girls)
Main Effect*
Child GenderX Mom P Birth
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Moderation Effect – Q6 D1 & 2 Mother’s Place of Birth will moderate the
association of child’s gender to pre-test parenting skills so that:
Among mother’s born in US
Among mother’s born in Mexico
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Moderation Effect Q6 D1 & 2 Mother’s Place of Birth will moderate the
association of child’s gender to pre-test parenting skills so that: Among Mothers born in US, there will be no
difference in the mean score of the parenting skills scale among mothers of boys compared to mothers of girls
Among mothers born in Mexico, mothers of boys will obtain higher mean scores in the parenting skills scale than mothers of girls
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IVDV- Pre-test
SR Parental Skills Scale F statistic
Mom Place of Birth
Mexico vs. US(regardless offspring gender )
Main Effect
Child Gender Boys vs. Girls(regardless Mom place birth)
Main Effect
Child Gender x Mom P. Birth
Mom Mexico: Boys vs. Girls
Mom US : Boys vs. Girls
Mom’s birth place as
moderator
Table 4: 2X2 ANOVA with Moderation Moderator: Moms P. of Birth
39
Table 1 Parenting Skills Main Effect: Mom’s Country of Birth and Child’s Gender
Main Effects
Parenting Scale Mean Mean
F statistic
Mom Birth Country
Mexico 2.8
USAns 3.0 p>.05
Target Child’s Gender
Mom of Girls2.4
Mom of Boys3.5*
*p<.05
Possible range of scores for parenting Scale = 1 to 5
40
Result Main Effects: Place of Birth Question #6 Table 5 Do moms born in USA obtain higher
scores in parenting skills than moms born in Mexico?
Answer: No 2.8 vs. 2.9 P>.05
41
Results Main Effects: Child’s Gender Question #6 Table 5 Do moms of boys obtain higher scores in
parenting skills than moms of girls? Answer: Yes, 3.3 vs. 2.3 p<.05
42
IVDV- Pre-test
SR Parental Skills Scale F statistic
Mom Place of Birth
Mexico vs. US(Mexico + USA)
Main Effect NS
Child Gender Boys vs. Girls(Boys + Girls)
Main Effect** p<.05
Child Gender x Mom P. Birth
M Born Mexico: Boys vs. GirlsM Born US : Boys vs. Girls
Mom’s birth place as moderator
Table 4: 2X2 ANOVA with ModerationDV- SR Parenting Scale – Moderator Mom place of birth
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Interaction Effects Study Q. #6: Moderator: Mom’s Place Birth
Does mom’s place of birth moderate (make a difference in) the association of child’s gender to mom’s parenting skills:
Mothers born in Mexico we may expect that:
Mothers born in US we may expect that
44
Interaction Effects Study Q. #6: Moderator: Mom’s Place Birth
Does mom’s place of birth moderate (make a difference in) the association of child’s gender to mom’s parenting skills:
Mothers born in Mexico we may expect that: Mother of boys will score higher in the SRPSS than mother of girls
Mothers born in US we may expect that
45
Interaction Effects Study Q. #6: Moderator: Mom’s Place Birth
Does mom’s place of birth moderate (make a difference in) the association of child’s gender to mom’s parenting skills:
Mothers born in Mexico we may expect that: Mother of boys will score higher in the SRPSS than mother of girls
Mothers born in US we may expect that Mother of boys and girls will not differ in in the SRPSS scores
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Table 2 Moderation EffectsMeans Parenting Skills Ratings by Child’s Gender Moderator: Mom’s Country of Birth
Mom of Girls
Mom of Boys
Born Mexico
1.9 3.8* *p<.05
Born USA
2.7
. 3.1 p>.05
47
Table 1 Parenting Skills Main & Moeration Effect: Moderator: Mom P. of Birth
Main Effects
Parenting Scale Mean Mean
F statistic
Mom Birth Country
Mexico 2.8
USA 3.0ns p>.05
Child’s Gender
Mom of Girls2.4
Mom of Boys3.5*
*p<.05
Child Gender x Mom P. Birth
Mom GirlsMom Mexico 1.9
Mom US 2.7
Mom of Boys 3.8*
3.1ns
*p<.05
Possible range of scores for parenting Scale = 1 to 548
Interaction Effects Study Q. #6: Moderator: Mom’s Place of Birth
Does mom’s place of birth moderates the association of child’s gender to parenting skills score? Yes Among Moms born in Mexico, moms of boys obtained
higher scores in parenting skills than moms of girls? 3.8* vs. 1.9 p<.05
Among Moms born in USA, moms of boys obtained similar scores in parenting skills than moms of girls? 3.1 vs. 2.5 NS
49
Conclusions Only among Mom’s born in Mexico, moms of
boys scored higher in the parenting skills questionnaire than mom’s of girls.
Among mom’s born in US no differences in parenting score by target child’s gender
Therefore, the main effect for child’s gender applies only to mom’s born in Mexico.
Findings support 2 of the 3 hypothesis
Is the SR-PSS a valid measures of parenting skills among Latina mothers?
50
Is SR-PSS a valid measures of parenting skills among Latina mothers?
The SR-PSS seems to assess endorsement of autonomy in child rearing practices
Latina mothers born in Mexico endorse higher levels of autonomy when target child is boy than when it is a girl – consistent with predominant values in Latino culture
Latina mothers born in US exhibit similar levels of parenting skills when target child is boy than when it is a girl – Born in US more highly acculturated to US child rearing values. 51
Comparison of Studies
Study Question #5 Question #6
IVs Both Manipulated Categorical
Both Status, Categorical
DVs Continuous; Parenting Skills Continuous: Parenting Skills
Design Experimental, factorial, Betw.-G Association, factorial, Betw-GAssignment Analyses Groups Random Assigned
Analysis ANOVA 2X2 ANOVA 2X2
52
Differences in Studies Questions #5 and #6 (1/2)
Nature of IVs and DVs # 5 Both Vs are manipulated
#6 Both IVs are inherent to participants
#5 & #6 IVs are categorical #5 & #6 DVs are continuous
Design #5 Experimental factorial #6 Expo-facto factorial 53
Differences Studies in Questions #5 and #6 (2/2)
Assignment of participants to conditions, #5 random #6 characteristic inherent to participants
Statistical analyses Both: ANOVA with interaction effects
Inferences from results #5 Causal vs. #6 Association 54
Survey or Expo- Facto What is the incidence of PTSD among
veterans from the IRAQ war: total, by gender and by ethnic group.
Is there an association between gender and ethnicity (B H W) and PTSD in veterans from the IRAQ war. Should we expect gender and ethnic
differences; why? 55
Survey Design Expo-Facto Design
o Document nature or frequency of a variable
o Association of status variable(s) to continuous variable(s)
o Descriptive: No theoretical or logical rational needed
o Test Hypotheses
o Probability samples o More tolerant of convenience samples
56