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

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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

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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.

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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?

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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

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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

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Second Study Question 6

Research Design

Independent Variables

Dependent Variables

Participants

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Second Study Question 6

Research Design Non-experimental - Association Factorial Between Groups

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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

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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:

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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

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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

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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

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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

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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

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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

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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: Mother of boys will score higher in the SRPSS than mother of girls

Mothers born in US we may expect that

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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: 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

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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

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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?

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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

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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

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