What is the mean of the sampling distribution of the difference between means? (relevant section)

Complete the following questions in a 1-3 page document formatted per APA Requirements. Be sure to use Version 1 of Online Statistics: An Interactive Multimedia Course of Study:http://onlinestatbook.com/version_1.html


The following questions use data from the Angry Moods (AM) case study.


  1. Lane, Chapter 7, exercise 25 (Angry Moods Study)


  1. Suppose in the population, the Anger-Out score for men is two points higher than it is for women. The population variances for men and women are both 20. Assume the Anger-Out scores for both genders are normally distributed. Given this information about the population parameters:


(a) What is the mean of the sampling distribution of the difference between means? (relevant section)

(b) What is the standard error of the difference between means? (relevant section)

(c) What is the probability that you would have gotten this mean difference (see #24) or less in your sample? (relevant section)


  1. Lane, Chapter 8, exercise 25 (Angry Moods Study)


(AM#10) Calculate the 95% confidence interval for the difference between the mean Anger-In score for the athletes and non-athletes. What can you conclude? (relevant section)


  1. Lane, Chapter 9, exercise 27 (Angry Moods Study)


For the following problem (#27) complete the three parts listed below:


(a) What is the 95% confidence interval on the difference between means? (relevant section)

(b) Based on your confidence interval, can you reject the null hypothesis at the .05 level? (relevant section)

(c) What do you conclude? (relevant section & relevant section)


  1. (AM#6) Is there a difference in how much males and females use aggressive behavior to improve an angry mood? For the “Anger-Out” scores, compare the means for each gender.








Case study prepared by: Emily Zitek


People have different ways of improving their mood when angry. We have all seen people punch a wall when mad, and indeed, previous research has indicated that some people aggress to improve their mood (Bushman, Baumeister & Phillips, 2001). What do the top athletes do when angry? Striegel (1994) found that anger often hurts an athlete’s performance and that capability to control anger is what makes good athletes even better. This study adds to the past research and examines the difference in ways to improve an angry mood by gender and sports participation.


The participants were 78 Rice University undergraduates, ages 17 to 23. Of these 78 participants, 48 were females and 30 were males and 25 were athletes and 53 were non-athletes. People who did not play a varsity or club sport were considered non-athletes. The 13 contact sport athletes played soccer, football, rugby, or basketball, and the 12 non-contact sport athletes participated in Ultimate Frisbee, baseball, tennis, swimming, volleyball, crew, or dance.

The participants were asked to respond to a questionnaire that asked about what they do to improve their mood when angry or furious. Then they filled out a demographics questionnaire.

Note: This study used the most recent version of the State-Trait Anger Expression Inventory (STAXI-2) (Spielberger, Sydeman, Owen & Marsh, 1999) which was modified to create an Angry Mood Improvement Inventory similar to that created by Bushman et al. (2001).


Questions to Answer

Do athletes and non-athletes deal with anger in the same way? Are there any gender differences? Specifically, are men more likely to believe that aggressive behavior can improve an angry mood?

Design Issues

This study has an extremely unbalanced design. There were a lot more non-athletes than athletes in the sample. In the future, more athletes should be used. This study originally wanted to look at contact and non-contact athletes separately, but there were not enough participants to do this. Future studies could look at this.

Descriptions of Variables


Variable Description
Sports 1 = athletes, 2 = non-athletes
Gender 1 = males, 2 = females
Anger-Out (AO) high scores demonstrate that people deal with anger by expressing it in a verbally or physically aggressive fashion
Anger-In(AI) high scores demonstrate that people experience anger but do not express it (suppress their anger)
Control-Out (CO) high scores demonstrate that people control the outward expression of angry feelings
Control-In (CI) high scores demonstrate that people control angry feelings by calming down or cooling off
Expression (AE) index of general anger expression:(Anger-Out) + (Anger-In) – (Control-Out) – (Control-In) + 48


Note: Description of the items comes from Spielberger et al. (1999).




Bushman, B.J., Baumeister, R.F. & Phillips, C.M. (2001). Do people aggress to improve their mood? Catharsis beliefs, affect regulation opportunity, and aggressive responding. Journal of Personality and Social Psychology, 81(1), 17-32.Spielberger, C. D., Sydeman, S. J., Owen, A. E., Marsh, B. J. (1999). Measuring anxiety and anger with the State-Trait Anxiety Inventory (STAI) and the State-Trait Anger Expression Inventory (STAXI). In M. E. Maruish (Ed.), The use of psychological testing for treatment planning and outcomes assessment (2nd ed., pp. 993-1021). Mahwah: Lawrence Erlbaum Associates.

Striegel, D. (1994). Anger in tennis: Part 2. Effects of anger on performance, coping with anger, and using anger to one’s benefit. Journal of Performance Psychology, 2, 56-92.


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