REFERENCE AT THE BOTTOM, I WILL COPY AND PASTE THE TABLE IF NEEDED!

Related-Samples t-tests

Surprised by her results on the first study, the same researcher decides to conduct another study focused on assessing the effectiveness of prayer. This time, she wants to avoid any human factor that could emerge as a confounding variable (e.g., placebo effect, discouragement etc.) so she used a sample of 20 bush babies (primates) who were infected with rhodesiense, a parasite that causes fever headaches, confusion, affects muscle coordination and disturbs the sleep cycle.These animals were diagnosed and then prayed for by a group of intercessors for 1 week, after which their symptoms were re-assessed to see if there was any improvement.Consequently, the symptoms of the primates were measured beforeand after the week of prayer.

The researcher would like to determine whether being prayed for made a difference in the health of the primates. In variable terms, the researcher wants to know if there is a mean difference between the before and after the week of intercession.

File titled "SPSS Assignment #2 - Related Samples T-Test data".

Step 1: Setting up your data

1. Input the data into SPSS or import it.
2. Label and code your data

before Width: 8

Decimals: 2

Label: health scores before prayer

Values: None

Missing: None

Columns: 8

Align: Center

Measure: Scale

Role: None

after Width: 8

Decimals: 2

Label: health scores after prayer

Values: None

Missing: None

Columns: 9

Align: Center

Measure: Scale

Role: None

For a repeated or paired-samples t-test, the normality tests are conducted on difference scores, not the values of the paired groups themselves. To accomplish this, you first need to compute the health scores difference and store them in a new variable.

Step 2: Answer the following questions

1. What are the independent and the dependent variables?
2. What are the scales of measurements of the independent and dependent variables?
3. What are the null and alternative hypotheses?
4. Are the hypotheses directional? What kind of test should we use (one-tailed or two-tailed)?
5. Name the assumptions that must be met for a dependent-samples t-test (refer to your textbook)
   1. Has the first assumption been met? Why or why not?
   2. Conduct tests of normality using the difference variable. Copy and paste the Shapiro-wilks table Has the assumption of normality been met? Why or why not?

Step 3: Dependent Samples t-test

1. Copy and paste your paired samples statistics tables and answer the following questions in full sentences, specify mean and standard deviations:
2. Under which condition did the bush babies have the better health on average?
3. Which condition had greater variability?
4. Effect size (Cohen's d)

• If you computed Compute Cohen's d effect size (1) enter the formula, (2) show your computations
• If you obtained Cohen's d from the Paired Samples Effect Sizes table in your SPSS output, copy and paste the table, The Cohen's d value is located in the 'point estimate'column

Then, (3) report your findings (what is the value of Cohen's d) and (4) comment on the magnitude of the effect. Is this a large, small or medium effect size?

1. Report the results of your related samples t-test (using A P A format) in one paragraph. Use the same example as the independent-samples t-test.

Make sure to specify (1) your decision and explain it, (2) what the results means (i.e., was prayer effective? Is there a significant in health before and after prayer? If yes which one?), (3) write up A P A style.