repeated -measures manova

8/3/2019 Repeated -Measures MANOVA

1/7

Repeated- measures MANOVA(DR SEE KIN HAI)

1. Each subject is tested under different conditions (Independent variables)i.e. within-subjects or repeated-measures design.

Example: You are to determine do different conditions / treatmentsgiven to students (ind vars) affect students achievement scores (depvar). (Use grades.sav)

(The same sample is given a same test (Dependent variable) under differentconditions / treatments (Independent variables)4 conditions: 2 different paper colours by 2 different ink colours with differentachievement scores (quiz1 to quiz4.)

How to run the MANOVA1. [Analyze] [General Linear Model] [Repeated Measures]

2. Enter ind vars,[papercol] and[inkcolor] in[Within SubjectFactor Name] then

enter [Number ofLevels] then[Add].

3. If there aremultiple dep varsfor each level ofwithin subjectdesign, then click

[Measures] to specify the deep measures.

1

Fig 1

Fig 2


2/7

4. In the [Measure Name] box type the name of each dep var used then click[Add]

Now [papercol] has 2 levels, and [inkcolor] has 2 levels match them with depvars [quiz1] to [quiz4] in the [Measure Name]

5. Now click on [Define] to specify the rest of the analysis

6. Move [quiz1] to [quiz4] inside [Within-Subject variables] box.7. Select [Model] then [Full factorial] giving all main effects and all

interactions. [Custom] chooses the main and interaction effects forparticular vars ony.

8. Select [Custom] move 1 var for main effects [Within-Subject Model] andinteractions move 2 or more vars [Between-Subjects Model], then[Continue] and [OK]

2

Fig 3


3/7

Procedure to run MANOVA (EXERCISE)

Exercise (1) (Within-Subjects Designs)To perform a 2 (paper color) by 2(ink color) within-subjects analysis of variance, with [quiz1] to [quiz4]Fig 1: Enter (papercol) into [factor1] and [Number of Levels] as (2), then [Add]

Enter (inkcolor) into [factor1] and [Number of Levels] as (2) , then [Add],then [Define]Fig 3: Move (Quiz 1) to (Quiz 4) into [Within-Subjects Variance] then [Options]

Fig 5: Select [Descriptive statistics], [Estimates of effect size], [Continue], [OK].

Exercise (2) (Mixed Designs) To produce a within-subjects and between-subjects using (gpa) as covariate in a 2 (ink color) by 2 (gender ofsubjects) MANOVA.Fig 1: Enter (inkcolor) into [factor1] and [Number of Levels] as (2) , then [Add],then [Define]

3

Fig 4

Fig 5


4/7

Fig 3: Move (Quiz 1) to (Quiz 4) into [Within-Subjects Variance]Move (sex) into [Between-Subjects Factors] and (gpa) into [Covariates],

[Options]Fig 5: Select [Descriptive statistics], [Estimates of effect size], [Continue], [OK].

Exercise (3) (Doubly-multivariate designs) To produce 2 or more

dependent variables in different levels of 1 or more within-subjectsfactors. (Here [quiz1] and [quiz2] = short-answer quizzes, [quiz3] and [quiz4] =multiple-choice quizzes, [quiz1] and [quiz3] taken under [green-ink color]condition, [quiz2] and [quiz4] taken under [black-ink color] condition.

Fig 1: Enter (inkcolor) into [factor1] and [Number of Levels] as (2), then [Add],then

[Measure]Fig 2: Enter (essay) into [Measure Name] , [Add] and (mc) into [Measure Name]then [Add],

Then [Define]

Fig 3: Move (Quiz 1) to (Quiz 4) into [Within-Subjects Variance] then [Options]Fig 5: Select [Descriptive statistics], [Estimates of effect size], [Continue], [OK].

Output of Within-Subjects and Repeated-measures MANOVA(Ex 1,2,3)

The main and interacting effects are presented. Here the interacting effect ofpaper color and ink color is significant ( p = 0.003), thus thee means of the cellsmust be examined to interpret this effect.

4


5/7

Here Black ink produces higher quiz scores than green ink when printed on bluepaper. However green ink produces higher quiz scores than black when printedon red paper.

Tests of Within-Subjects Effects(For Ex 1 and 2)

Here F values and significant levels are given.

5


6/7

Univariate Tests(For Ex 3)

The doubly-multivariate designs (more than 1 dep var)with univariate F tests areperformed for each main and interaction effects. There is a sig effect of ink colorand essay exam but not for MCQ exams. Few methods of calculation are used(Sphericity Assumed, Greenhouse-Geisser, Huynh-Feldt ) with similar results.

6


7/7

Tests of Between-Subjects Effects(For Ex 2)

The between-subjects effects are listed with thee effects of covariates. All theseresults will be covered by the MANOVA above.

Coursework

364 male and female subjects completed a personality inventory comprising aself-esteem, optimism and hope scale. The researcher is aware that these

subscales are highly correlated. Use Prac 18.sav for your work.

1. Check for violations of assumptions.2. Determine whether gender differences exist across the combination of

scales.

7

repeated -measures manova

Documents