Question

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: Run and save the Codebook for your SPSS data file

Step 2: 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 3: 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 4: Review your SPSS output and answer each of the following questions:

From the independent samples t-test output:
What is the mean CHNG_ENDUR for group 1?	________________	____ / 3 points
What is the CHNG_ ENDUR standard deviation for group 1?		____ / 3 points
What is the mean CHNG_ENDUR for group 2?	________________	____ / 3 points
What is the CHNG_ ENDUR standard deviation for group 2?	________________	____ / 3 points
What is the value of the t statistic (equal variances assumed)?	________________	____ / 3 points
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]?	________________	____ / 3 points
Are the results statistically significant at alpha = 0.05 (yes or no)?	________________	____ / 3 points
Based on the results, do you reject or fail to reject the null hypothesis?	________________	____ / 3 points
From the ANOVA output:
What is the mean CHNG_ENDUR for males?	________________	____ / 3 points
What is the CHNG_ENDUR standard deviation for males?	________________	____ / 3 points
What is the mean CHNG_ENDUR for females?	________________	____ / 3 points
What is the CHNG_ENDUR standard deviation for females?	________________	____ / 3 points
What is the calculated F-value?	________________	____ / 3 points
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?	________________	____ / 3 points

ID	AGE	SEX	EXERCISE	CHNG_ENDUR
1	53	1	2	5
2	62	2	2	2
3	34	1	1	6
4	38	1	1	5
5	39	1	1	4
6	27	1	2	5
7	18	2	1	7
8	19	1	1	4
9	49	1	2	4
10	60	1	1	3
11	22	1	2	7
12	54	1	1	5
13	55	2	2	3
14	38	1	2	8
15	62	2	1	6
16	31	1	1	5
17	63	2	2	3
18	41	1	1	4
19	29	2	2	4
20	33	1	1	6
21	26	2	2	8
22	22	1	2	3
23	43	2	1	6
24	29	2	1	3
25	48	2	2	4
26	29	2	2	3
27	53	1	1	4
28	37	2	2	5
29	25	2	1	6
30	42	1	2	3
31	43	2	1	5
32	39	2	2	3
33	45	1	1	4
34	31	1	2	2
35	57	2	2	3
36	27	2	1	3
37	49	2	1	3
38	35	2	2	2
39	27	2	1	5
40	50	1	2	4

Answer 1

Solution:

From the independent samples t-test output:	Answer
1. What is the mean CHNG_ENDUR for group 1?	4.70
1. What is the CHNG_ ENDUR standard deviation for group 1?	1.218
1. What is the mean CHNG_ENDUR for group 2?	4.05
1. What is the CHNG_ ENDUR standard deviation for group 2?	1.820
1. What is the value of the t statistic (equal variances assumed)?	1.327
1. 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]?	(p = 0.192) 19.20% Chance
1. Are the results statistically significant at alpha = 0.05 (yes or no)?	No (nonsignificant)
1. Based on the results, do you reject or fail to reject the null hypothesis?	Fail to reject the null hypothesis
From the ANOVA output:
1. What is the mean CHNG_ENDUR for males?	4.55
1. What is the CHNG_ENDUR standard deviation for males?	1.432
1. What is the mean CHNG_ENDUR for females?	4.20
1. What is the CHNG_ENDUR standard deviation for females?	1.704
1. What is the calculated F-value?	0.494
1. 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?	(p = 0.486) 48.60% Chance