In addition to their age levels, the movie audiences in Exercise 2 were also asked if they had seen the movie before (Never, Once, More than Once). Here is a table showing the responses by age group:
a) Find the marginal distribution of their previous viewing of the movie. (Hint: Find the row totals.)
b) Verify that the marginal distribution of the ages is the same as that given in Exercise 2.
For the ages described in Exercise 2:
a) Write two to four sentences summarizing the distribution.
b) What possible problems do you see in concluding that the age distribution from these surveys accurately represents the ages of the national audience for this film?