Recall Exercise 7.2.40 on the effect of music on chimpanzees. The researchers also kept track of the total number of aggressive events each chimpanzee displayed and divided these by the total time that an individual was present in the condition. This gives the rates of aggression per individual per hour in the music condition and in the no music condition. Only the 11 chimpanzees that showed any aggression were included in this analysis. We would like to investigate whether there was a significant difference in the aggression rates between the music and no music conditions. The data can be found in the file MusicAggression. Put the data in the Matched Pairs applet to answer (a)–(d). 

a. What are the mean rates of aggression for each condition (music and no music)? Which condition resulted in the higher aggression rate on average? 

b. What is the average difference in the number of rates of aggression (music – no music)? 

c. Appropriately randomize at least 1,000 times and determine a p-value. 

d. State a conclusion based on your p-value.

Data from Exercise 7.2.40

You may have heard the phrase “Music soothes the savage beast,” which is actually a misquote of a line of poetry by William Congreve. Researchers (Wallace et al., 2017) examined what effect music had on captive chimpanzees. In particular, they compared the number of incidences of social behavior described as playing, grooming another chimpanzee, or being groomed by another chimpanzee in an environment when music was playing versus the same chimpanzee behavior when no music was playing. We want to test to see whether, on average, there is difference in the number of incidences of social behavior with the chimpanzees between when music is present and when it is not. Put the data from the file MusicSocial in the Matched Pairs applet to answer (a)–(e).