How does the presence of humans affect the population of sparrows in a park? Do more humans mean fewer sparrows? Or does the presence of humans increase the number of sparrows up to a point? Are there a minimum number of sparrows that can be found in a park, regardless of how many humans are there? What can a mathematical model tell you? In 1997, researchers set out to answer these questions. They observed the sparrow population and the numbers of pedestrians in wooded parks. Their approximate data can be seen below.