Mrs. liang, the librarian, wants to compare the numbers of
patrons who prefer e-books to paperback books. she
decides to take a poll of every third adult with a child who
arrives at the library for one of the four reading groups:
toddlers, preschoolers, primary grades, and upper
elementary. which statement is true about her method of
data collection?
a) it is not balanced because it is less likely to include
teens, young adults, and senior citizens in the patron
population
b) it is balanced because she is polling four different
reading groups, which include all types of people