State whether each of the following data sets is quantitative or qualitative.
a. Arrival times of 16 reflected seismic waves
b. Types of computer software used in a database management system
c. Brands of calculator used by 100 engineering students on campus
d. Ash contents in pieces of coal from three different mines
e. Mileages attained by 12 automobiles powered by alcohol
f. Life-lengths of laser printers
g. Shift supervisors in charge of computer operations at an airline company
h. Accident rates at 46 machine shops