Module 5 Correlation Worksheet

Name: _____________________

In this assignment, you will use the SPSS Analysis Data Set and SPSS software to run correlations and create scatterplots.

Research Scenario

A researcher is interested in the effect of a new medication on blood glucose and white blood cell levels of adults. The researcher randomly selects a sample of 60 (30 male and 30 female) participants with higher-than-normal WBC count.

Assuring equal distribution of males and females, the participants are randomly assigned to one of two conditions (or groups): medication or placebo. Following pretest measures of blood glucose (BLOODGL) and white blood cell (WBC) levels, the experimental group (GROUP 1) is given the medication for a period of six months while the control group (GROUP 2) is given a placebo. After the six months, BLOODGL and WBC are measured again. The researchers also ask if participants have ever been diagnosed with two forms of cancer that cause high WBC count: leukemia and lymphoma (CANCER).

The post-test data for each participant are provided in the SPSS Analysis Data Set located in the Learning Resources. The codebook for the data is as follows:

Codebook

Variable Name	Label
AGE	Age in years
SEX	1 = male, 2 = female
GROUP	1 = medication, 2 = placebo
BLOODGL	Blood glucose level (70-250 mg/dL)
WBC	White blood cell count (11,000-100,000 per microliter)
CHNG_WBC	Change in white blood cells from pre-test to post-test
CANCER	0 = never diagnosed, 1 = cancer diagnosis (leukemia or lymphoma)

Begin by downloading the SPSS Analysis Data Set (.sav file) to your computer and complete the following steps:

Step 1: Open Data Set

• Open the SPSS software.
• Locate the SPSS Analysis Data Set in your files.
• Click on "Open" and then "OK".

Step 2: Run Correlations on Combinations of Continuous Variables

• In the top menu bar, select Analyze > Correlate > Bivariate Correlations.
• Highlight AGE and BLOODGL. Click on the arrow button to move them over to the "Variables" box.
• Under "Correlation coefficients," select "Pearson".
• Under "Test of significance," select "Two-tailed".
• Check the "Flag significant correlations" box.

Note: We haven't talked about significance tests yet. For now, just know that they mean there is something important about the association between variables.

• Click on "OK".
• Repeat these steps for AGE and WBC as well as BLOODGL and WBC.

Step 3: Review SPSS Output and Answer the Following Questions

QUESTION	Type answers below
1. What is the Pearson correlation value for AGE and BLOODGL?
2. What is the probability [Sig (2-tailed)] for the correlation between AGE and BLOODGL?
3. Is the correlation between AGE and BLOODGL flagged for significance?
4. What is the Pearson correlation value for AGE and WBC?
5. What is the probability [Sig (2-tailed)] for the correlation between AGE and WBC?
6. Is the correlation between AGE and WBC flagged for significance?
7. What is the Pearson correlation value for BLOODGL and WBC?
8. What is the probability [Sig (2-tailed)] for the correlation between BLOODGL and WBC?
9. Is the correlation between BLOODGL and WBC flagged for significance?
10.If the probability for Pearson correlation is less than 0.05, we assume a significant relationship between the variables. Is there a significant relationship between BLOODGL and WBC?

Step 4: Create Scatterplots on Combinations of Continuous Variables

• Click on Graphs > Legacy Dialogs > Scatter/Dot.
• Select "Simple Scatter"
• Highlight AGE. Click on the arrow button to move it over to the "Y-axis" box.
• Highlight BLOODGL. Click on the arrow button to move it over to the "X-axis" box.
• Click on "OK".
• Repeat these steps for AGE (Y-axis) and WBC (X-axis) as well as BLOODGL (Y-axis) and WBC (X-axis).

Step 4:Export SPSS Output to Word

• In the Output window, select File > Export.
• Under "Objects to Export," select "All".
• From the "Type" drop-down list, select "Word/RTF" (*.doc).
• In "File Name," give the output a unique name (e.g., OUTPUT_Module5Corr). (Note the file folder where the Word document will be saved. The default is typically C:\Documents.)
• Click on "OK" to generate the Word file.

Step 5: Copy-and-Paste Correlations Tables and Scatterplots to Worksheet

• Copy the following tables/graphs from the Output Word file and paste them below.
  • Correlations tables for AGE*BLOODGL, AGE*WBC and BLOODGL*WBC
  • Scatterplots for AGE*BLOODGL, AGE*WBC and BLOODGL*WBC