(10 points) 7. Create a times series plot for the rates of all diseases in the United States. Use the previous exercises as examples. library(dplyr) library(ggplot2) library(dslabs) library(RColorBrewer) data(us_contagious_diseases) Start with the code above and: a. Compute the US rate by using summarize to sum over the states. i. The US rate for each disease will be the total number of cases divided by the total population. Be sure to convert to cases per 10,000. b. You will need to filter for !is.na(population) to get all the data. c. Plot each disease in a different color. d. Take a screen shot of both your code and the console window. Paste this image into your solution document. Be sure to include your graph.