Module 6 Application Assignment Worksheet

SPSS Hypothesis Testing

Instructions

For this assignment, you perform a two-sample independent t-test, an ANOVA, and a correlation analysis related to the data set that has been utilized in the previous two modules. Import the data into SPSS or, if you correctly saved the data file from the Module 4 and 5 Assignments, you may open and use that saved file to complete this Assignment. Type your answers to all questions directly into the worksheet, and paste the required output at the end of this document.

Submit this Application Assignment by Day 7 of Week 11.

Research Scenario

A researcher is interested in the effect of a new medication on serum cholesterol, HDL cholesterol, and glycosylated hemoglobin of adults.  The researcher randomly selects a sample of 40 (20 male and 20 female) participants who have been diagnosed with high cholesterol. Assuring equal distribution of males and females, the participants are randomly assigned to one of two conditions (or groups):  Following pretest measures of serum cholesterol (chol), high-density lipoprotein cholesterol (HDL), and glycosylated hemoglobin (glyhb), the experimental group (Group 1) is given the medication for a period of 6 months while the control group (Group 2) is given a placebo.  After the 6 months, chol, HDL, and glyhb are again measured.

The posttest data for each participant are provided in the Module 4 Application Assignment Data Set Excel file and can be found in the Module 6 Learning Resources. The codebook for the data provided is as follows:

AGE                Age in years

SEX                1 = male, 2 = female

GROUP         1 = medication, 2 = placebo

CHNG_CHOL           change in cholesterol from pretest to posttest

HDL                High-density lipoprotein at posttest

GLYHB                      Glycosylated hemoglobin at posttest

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Step 1: Import the Microsoft Excel data file into SPSS or use the correct saved SPSS data file as noted in the instructions above.

Step 2: Conduct an independent samples t-test to determine if there is a difference between Group 1 (medication) and Group 2 (placebo) in terms of changes in cholesterol values. Note that the independent variable is GROUP, and the dependent variable is CHNG_CHOL. For this analysis, choose a two-tailed test of significance. (Be sure to save your output.)

Step 3: Conduct a between-subjects ANOVA to determine if there is a difference between sex (males vs. females) and HDL. Note that the independent variable is SEX, and the dependent variable is HDL. For this analysis, choose a two-tailed test of significance. (Be sure to save your output.)

Step 4: Conduct a Pearson correlation to determine if there is a relationship between HDL and GLYHB. For this analysis, choose a two-tailed test of significance. (Be sure to save your output.)

Step 5: Review your SPSS output and answer each of the following questions:

From the independent samples t-test output:

1. What is the mean CHNG_CHOL for Group 1? _____________
2. What is the CHNG_CHOL standard deviation for Group 1? _____________
3. What is the mean CHNG_CHOL for Group 2? _____________
4. What is the CHNG_CHOL standard deviation for Group 2? _____________
5. What is the calculated t-score (equal variances assumed)? _____________
6. What is the probability that the obtained t-score was simply due to chance as opposed to actual gender differences [see “Sig (two-tailed)” on output]? _____________
7. If the probability associated with the obtained t-score is <0.05, we assume the results (difference in mean CHNG_CHOL between groups) are much more likely due to the effects of the medication than to chance. In other words, we would say the results are statistically significant. Are the results statistically significant (yes or no)?  ________

From the ANOVA output:

1. What is the mean HDL for group males? _____________
2. What is the HDL standard deviation for males? _____________

• What is the mean HDL for group females? _____________

1. What is the HDL standard deviation for females? _____________
2. What is the calculated F-value? _____________
3. What is the probability (noted as “Sig” on output) that the obtained F-value was simply due to chance as opposed to actual gender differences? _____________

From the correlation output:

1. What is the Pearson correlation score for HDL and GLYHB? __________
2. What is the direction of the correlation value and what does this mean? ______________________________________________________

______________________________________________________

1. What is the probability for the obtained Pearson correlation score [see “Sig (two-tailed)” on output]? _____________
2. If the probability associated with the Pearson correlation is <05, we assume a significant relationship. Is there a significant relationship between HDL and GLYHB? __________

Step 6: Paste all required SPSS output below.