Question

There are many programs that seek to change behavior. Social Psychologists conducted a study to increase sharing behavior in children during play when they were given their favorite toys. One way to assess the effect of a program is to give a pretest, administer the program, and give a posttest. To really prove the lasting value of the program, however, a researcher must gather follow-up data some months later to see if the improvement seen at posttest has continued. In the scores below, larger numbers represent more sharing behavior during play. Please conduct an ANOVA and state whether the program was effective in increasing sharing behavior.

                    pre   post     1yr follow-up ?

Subject 1            09        23       18              50

Subject 2            13            27         24               64

Subject 3            17            36             26              79

Subject 4            18        31             20               69

sums                   57           117            88          SC_tot = 262          SC²_tot = 6354

means              14.25         29.25    22.00

A. Write your null and alternate hypothesis using stat symbols

B. What is the Independent and Dependent variables?

C. How many levels of the IV do you have in this study?

D. Conduct all the necessary calculations/ analyze the data, compile it into a summary table: you must upload all of the work behind the figures that you placed in the table

E. Make an HSD comparisons between pre-test and one year follow?

F. Calculate the effect size for both comparisons in E.

D. Write an interpretation that describes the effects of the program.Write your conclusion/interpretation as seen in your video/lecture/text examples beginning with the reject or fail to reject the null hypothesis. Don't forget to include the effect size and all your stat symbols

SOURCE	SS	df	MS	F	p
pre/post/followup
Error
subjects
TOTAL

Answer 1

A. Write your null and alternate hypothesis using stat symbols

Ans: For pre/post/followup

Null hypothesis: All the mean score of pre/post/followup are same.

Alternative hypothesis: At least one mean has significant difference among pre/post/followup .

For Subject.

Null hypothesis: The mean scores between the subjects are same

Alternative hypothesis: At least one means has significant difference among subjects.

B. What is the Independent and Dependent variables?

Independent variables are pre/post/ followup and subject.

Dependent variable is scores.

C. How many levels of the IV do you have in this study?

Ans: What is the level IV ?????????????

Here, pre/post/ followup variable has 3 levels and subjects has 4 levels.

D. Conduct all the necessary calculations/ analyze the data, compile it into a summary table: you must upload all of the work behind the figures that you placed in the table

E. Make an HSD comparisons between pre-test and one year follow?

Ans:

From the above table, the estimated p-value for comparison pre and 1st year followup is 0.011. Hence, there is the significant difference in mean score between these levels.

F. Calculate the effect size for both comparisons in E.

The effect size =450.167/633.667=0.7104.

D. Write an interpretation that describes the effects of the program.Write your conclusion/interpretation as seen in your video/lecture/text examples beginning with the reject or fail to reject the null hypothesis. Don't forget to include the effect size and all your stat symbols

Ans: The estimated p-value of Pre/post/1st is less than 0.05 level of significance. Hence, reject the null hypothesis and conclude that there is at least one means has a significant difference among Pre/post/1st.

The estimated p-value of Subject is less than 0.05 level of significance. Hence, reject the null hypothesis and conclude that there are at least one means has a significant difference among subject levels.

Source	DF	SS	Effect size
Pre/post/1st	2	450.167	0.7104157
Subject	3	145.667	0.2298794
Error	6	37.833	0.0597049
Total	11	633.667

Two-way ANOVA: Score versus Pre/post/1st, Subject

Source	DF	SS	MS	F	P-value
Pre/post/1st	2	450.167	225.083	35.70	0.0000
Subject	3	145.667	48.556	7.70	0.0180
Error	6	37.833	6.306
Total	11	633.667

S = 2.511 R-Sq = 94.03% R-Sq(adj) = 89.05%