The U.S. Bureau of Labor Statistics provides data on the year-to-year percentage changes in the wages and salaries of workers in private industries, including both “white-collar” and “blue-collar” occupations. Here we consider these data for the years 1980-1996 in the file P2 56.X1LS. S 

a. Is there evidence of a strong relationship between the yearly changes in the wages and salaries of “white-collar” and “blue-collar” workers in the United States over the given time period? Describe the nature of any observed systematic relationship between these two variables.

b. Construct graphs for each of the three given time series and comment on any observed trends in these data.