# problem-7.31

problem-7.31 We might envision the collection of songs on an album as coming from a population of all possible songs the band could have written at the given time. A difference of means would indicate a tendency to write longer songs at one of the given times.
The only trick to finding the confidence interval is referencing the times from The Joshua Tree. This needs to be quoted.

    > wilcox.test(u2$October,u2$"The Joshua Tree", conf.int=TRUE)

The calculated interval is [-94,10].