Question

exercise and the tukey hsd test: in how it works 11.1, we conducted a one-way between-groups...

exercise and the tukey hsd test: in how it works 11.1, we conducted a one-way between-groups anova on an abbreviated data set from research by irwin and colleagues (2004) on adherence to an exercise regimen. Participants were asked to attend a monthly group education program to help them change their exercise behavior. Attendance was taken and participants were divided into three categories: those who attended fewer than 5 sessions, those who attended between 5 and 8 sessions, and those who attended between 9 and 12 sessions. The dependent variable was number of minutes of exercise per week. Here are the data once again:

<5 sessions: 155, 120, 130,

5-8 sessions: 199, 160, 184,

9-12 sessions: 230, 214, 195, 209.

a) What conclusion did we draw in step 6 of the ANOVA? Why could you not be more be more specific in your conclusion? That is, why is an additional test necessary when the ANOVA is statistically significant?

b) Conduct a Tukey HSB test for this example. State your conclusions based on this test. Show all calculations.

c) If we did not reject the null hypothesis for a particular pair of means, then why cant we conclude that the two means are the same?

Homework Answers

Answer #1

(a) The hypothesis being tested is:

H0: µ1 = µ2 = µ3

Ha: Not all means are equal

<5 sessions 5-8 sessions 9-12 sessions
155 199 230
120 160 214
130 184 195
209
Mean n Std. Dev
135.0 3 18.03 <5 sessions
181.0 3 19.67 5-8 sessions
212.0 4 14.45 9-12 sessions
179.6 10 36.85 Total
ANOVA table
Source SS    df MS F    p-value
Treatment 10,172.4 2 5,086.2 17.37 .0019
Error 2,050.00 7 292.857
Total 12,222.4 9

The p-value is 0.0019.

Since the p-value (0.0019) is less than the significance level (0.05), we can reject the null hypothesis.

Therefore, we can conclude that there is a significant difference between the group means.

(b) Using the Tukey Method and 95% Confidence

Factor N Mean Grouping
9-12 sessions 4 212.00 A
5-8 sessions 3 181.0 A
<5 sessions 3 135.0 B

Means that do not share a letter are significantly different.

There is a significant difference between the means of 9-12 sessions and <5 sessions.

There is a significant difference between the means of 5-8 sessions and <5 sessions.

(c) There is no significant difference between the means of 9-12 sessions and 5-8 sessions between their confidence intervals overlap.

Please give me a thumbs-up if this helps you out. Thank you!

Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
ADVERTISEMENT
Need Online Homework Help?

Get Answers For Free
Most questions answered within 1 hours.

Ask a Question
ADVERTISEMENT