14. The Recording Industry of America keeps track of recorded music sales by type of music, format, and age group. The following data show the percentage of music sales by type (The New York Times 2002 Almanac).

a. Is the type of music a qualitative or quantitative variable?

b. Construct a graph of rock music sales over the five-year period; use the horizontal axis to display the year and the vertical axis to display the percentage of music sales. Is this graph based on cross-sectional data or time series data?

c. Construct a bar graph for type of music sales in 2000. Is this graph based on crosssectional data or time series data?