To interpret the slope of \(-0.5\) in the context of the graph you're referring to, we can summarize it as follows:
The slope of \(-0.5\) indicates that for each year that passes, the percent of freshmen who plan to major in Business decreases by \(0.5%\).
So, to answer Part (c) specifically:
The decrease in the percent of freshmen per year who planned to major in Business is \(0.5%\).
This means on a yearly basis, fewer freshmen are choosing to major in Business by this percentage amount.