For each of the following examples, indicate whether it involves the use of descriptive or inferential statistics. Justify your answer.
a. The number of unemployed people in the United States
b. Determining students' opinion about the quality of food at the cafeteria based on a sample of 100 students
c. The national incidence of breast cancer among Asian women
d. Conducting a study to determine the rating of the quality of a new smartphone, gathered from 1,000 new buyers
e. The average GPA of various majors (e.g., sociology, psychology, English) at your university
f. The change in the number of immigrants coming to the United States from Southeast Asian countries between 2005 and 2010