Assignment: Comparing Two Means: When Drink Drove a Student to Statistics

The t-test is a frequently used statistical procedure that compares the means of two groups. There are two versions of the test based on whether the two groups are matched or not matched. Matched groups (also known as paired groups or samples) share many common characteristics, whereas unmatched groups (or independent groups or samples) do not. You must be able to identify which version of the t-test should be used in a given situation.

For this Assignment, review this week's Learning Resources. Reflect on how you may use the dataset to perform statistical tests in SPSS. Complete the worksheet provided in this week's Learning Resources.

The Assignment

Complete the Week 7 Assignment Worksheet provided by your instructor. Be sure that your completed worksheet contains the SPSS codebook for your data file, your responses to all questions, and all of the required SPSS output.

Instructions

For this assignment, you review this week's Learning Resources and then perform a two-sample independent t test and an ANOVA related to the dataset that was utilized in the week 2 SPSS application assignment. Import the data into SPSS; or, if you correctly saved the data file in Week 2, 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.

Research Scenario

A study was conducted to determine if a walking plus strength training exercise program results in a significantly greater increase in aerobic capacity as compared to a walking only exercise program. Participants are randomly selected and then randomly assigned to one of the exercise groups. Participants' aerobic endurance was assessed at the beginning of the study and, again, after 6-months of exercise.

Coding for study variables:
- AGE-age in years
- SEX-1 =male, 2=female
- EXERCISE-1= walking and strength training; 2 = walking;
- CHNG_ENDUR-change in maximal oxygen uptake (liters per minute) from pre-test to post-test

Step 1: Review this week's Learning Resources.

Step 2: Import the Microsoft Excel data file provided in this week's Learning Resources into SPSS (or open saved file from Week 2 Application Assignment).

Step 3: Run and save the Codebook for your SPSS data file

Step 4: Conduct an independent samples t test to determine if there is a difference between the exercise type 1 in terms of changes in maximal oxygen uptake. Note that the independent variable is EXERCISE, and the dependent variable is CHNG_ENDUR. For this analysis, choose a two-tailed test of significance.

Step 5: Conduct a between-subjects ANOVA to determine if there is a difference between sex (males vs. females) and CHNG_ENDUR. Note that the independent variable is SEX, and the dependent variable is CHNG_ENDUR. For this analysis, choose a two-tailed test of significance.

Step 6: Review your SPSS output and answer each of the following questions:

QUESTION
From the independent samples t-test output:

1. What is the mean CHNG_ENDUR for group 1?

2. What is the CHNG_ ENDUR standard deviation for group 1?

3. What is the mean CHNG_ENDUR for group 2?

4. What is the CHNG_ ENDUR standard deviation for group 2?

5. What is the value of the t statistic (equal variances assumed)?

6. What is the probability that the obtained t statistic was simply due to chance as opposed to actual exercise type differences [see "Sig (two-tailed)" on output]?

7. Are the results statistically significant at alpha = 0.05 (yes or no)?

8. Based on the results, do you reject or fail to reject the null hypothesis?
From the ANOVA output:

9. What is the mean CHNG_ENDUR for males?

10. What is the CHNG_ENDUR standard deviation for males?

11. What is the mean CHNG_ENDUR for females?

12. What is the CHNG_ENDUR standard deviation for females?

13. What is the calculated F-value?

14. 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?

Step 7: Paste the SPSS Codebook output below.

Step 8: Paste the independent samples t-test output below.

Step 9: Paste the ANOVA output below.

Attachment:- Assign data.xls