STAT480 - HW8 - Solved

Any code based on code from elsewhere must reference in comments the source of the original code. Code files must be the actual code files, not code pasted into some other document.  

 

All exercises are based on the USArrests dataset from R. This data set contains some state-wise arrest statistics as well as urban populations for all states in the US in 1973. Recall that some plotting functions expect a matrix and some expect a data frame, so you will need to use modified copies of the data when necessary.

 

Use options to add clear labels and titles to your plots, and avoid the default data$variable labeling in your plots.

Exercise 1: 

Obtain a heatmap based on the USArrests data set, and interpret the plot.

 

Specifically, comment on which states have higher and lower values of these statistics, comment on any apparent relationships between these crime rates and urban population, and comment on groups of states that are the most similar with respect to these statistics and groups of states that are very different with respect to this statistics.

Exercise 2: 

The state data set in R contains some basic information about the states in the United States in 1975. The states are in alphabetical order in the state data set and in the USArrests data set, so it is easy to directly combine information from them.  

 

Combine the USArrests data with the region and abbreviation (abb) variables from the state data set to create a data set for the treemap exercises.

 

Use a treemap to compare state-by-state urban population and assault rates, grouping by region within the plot.  

 

Comment on urban populations and assault rates by region and within region.  What were the general differences between regions at the time? What were the differences within regions? Which states had the highest and lowest urban populations and assault rates overall in 1973, and which were highest and lowest within regions.

Exercise 3: 

Repeat Exercise 2 with murder and assault rates instead of urban population and assault rates.  

Exercise 4: 

Create visualizations of the following three kernel density estimations.

 

•       Murder rate and assault rate

•       Murder rate and urban population

•       Assault rate and urban population

 

Be sure to choose bandwidths that provide reasonable refinement for the density estimation (not overly smoothed or under-smoothed). Comment on what the estimations tell us about more common magnitudes of the arrest rates and urban populations at the time, and what the plots tell us about relationships between the arrest rates and between the arrest rates and urban population in 1973.