Aresearcher wishes to study developmental changes in people’s preference for action movies. the researcher locates 50 people at each of the following ages: 15, 20, 25, 30, 35, 40, 45, and 50 years. she asks them to rate their preference for action movies in relation to other sorts of movies. this is an example of which type of design?
a. longitudinal
b. nested
c. cross-sectional
d. panel