PSYCHOLOGY STATISTICS

PSYC 355

SPSS Homework 4 Instructions: Two-Way Analysis of Variance

(40 points)

Part One: Note: For the two-way ANOVA, you will be expected to create a line graph as covered in the SPSS tutorial in the Course Content (and not a boxplot as in the textbook). This applies to future cumulative questions as well.

Problem Set 1: The Two-way ANOVA

File: Open “Module 4 Exercise File 1” found in Blackboard Course Content (Course Guides and Assignment Instructions—Assignment Instructions—SPSS Homework—SPSS Homework 4 Files).

Research Scenario: Because low birth weight contributes to health issues later on, a pregnancy center wants to educate mothers about the effects of smoking and not eating well during pregnancy on the birth weight of the baby. They gather data from local hospitals, including whether or not the mother smokes, whether or not she has a history of diet-related hypertension, and the eventual birth weight of the baby. Run a two-way ANOVA to determine whether birthweight differs as a function of smoking or hypertension in the mother.

1. Paste SPSS output. (4 pts)

2. Is the center correct in asserting that diet-related hypertension has a significant effect on birth weight? How do you know this? (4 pts)

3. Produce a line graph instead of a boxplot for this problem. Follow directions in course SPSS tutorial for setting up a line graph. (4 pts)

4. Write an APA-style Results section based on your analyses. All homework “Results sections” should follow the example given in the SPSS tutorials and the Course Content document “Writing Results of Statistical Tests in APA Format” (note: you do not have to refer to a figure). Remember to include a decision about the null hypothesis. For the two-way ANOVA, be sure to include statistical statements concerning the F ratios and p values for both main effects and the interaction, and interpretation statements about all 3 of these effects. (4 pts)

Part Two:

Problem Set 1: The Two-Way ANOVA

Research Scenario A group of clinical psychologists sets up a treatment study to look at the effects of treatment type and treatment setting (community clinic or university clinic) on symptom severity in a sample of patients with diagnosed Major Depressive Disorder. They recruit 12 participants from each type of clinic (though one person eventually drops out of one group), and divide them further into two groups, one of which receives cognitive-behavioral therapy (CBT) and one of which receives psychodynamic (PD) therapy. The psychologists measure depressive symptomology using the Beck Depression Inventory (Beck et al., 1961), and scores can range from 0 to 62. Their results are in the table below. Conduct a two-way ANOVA to determine whether treatment type and/or treatment setting have an effect on the severity of depressive symptoms.

	Community Clinic	University Clinic
CBT	36 32 19 25 27	31 12 27 20 29
PD	24 41 38 12	42 21 37 53 19

a. Paste SPSS output. (4 pts)

b. Produce a line graph instead of a boxplot for this problem. Follow directions in course SPSS tutorial for setting up a line graph. (4 pts)

c. Write an APA-style Results section based on your analyses. All homework “Results sections” should follow the example given in the SPSS tutorials and the Course Content document “Writing Results of Statistical Tests in APA Format.” Remember to include a decision about the null hypothesis. For the two-way ANOVA, be sure to include statistical statements concerning the F ratios and p values for both main effects and the interaction, and decisions about the null hypotheses for all 3 of these effects. (4 pts)

Part Three: Cumulative Homework

Problem Set 1: Choose the correct method from tests learned in previous modules.

Research Scenario: As part of a new treatment initiative, a residential substance abuse treatment center decides to assess clients at intake with the CMRS (De Leon, 1993) to determine their readiness to enter and remain in the treatment program. The scale has possible scores up to 90, with higher scores indicating a higher likelihood of entering and staying in the residential program. Counselors want to determine whether there are differences in CMRS scores between three main groups: patients with alcohol dependency, patients with heroin dependency, and patients with cocaine or crack cocaine dependency. A preliminary sample of scores is shown below. Is there a difference in CMRS scores among these three groups? Choose the correct test, then follow the directions after the table.

Alcohol	Heroin	Cocaine/ Crack Cocaine
56 32 57 45 79 22 61	43 80 67 32 24 18	68 31 51 45 29 63

a. Paste appropriate SPSS output. (4 pts)

b. Paste appropriate SPSS graph. (4 pts)

c. Write an APA-style Results section based on your analyses. All homework “Results sections” should follow the example given in the SPSS tutorials and the Course Content document “Writing Results of Statistical Tests in APA Format” (note: you do not have to refer to a figure). Remember to include a decision about the null hypothesis. (4 pts)

Submit this assignment by 11:59 p.m. (ET) on Monday of Module/Week 4.

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