Final answer:
The cowboy's graph showing possible mixes of output for fence mending and cattle herding is called a Production Possibilities Frontier (PPF), which illustrates the tradeoffs of his time allocation.
Step-by-step explanation:
The cowboy's Production Possibilities Frontier (PPF) graph serves as a visual representation of the tradeoffs and opportunity costs inherent in allocating his limited time between two productive activities: mending fences and herding cattle. The curve on the graph showcases the maximum achievable outputs for each activity, considering the fixed amount of resources, in this case, the cowboy's time.
As the cowboy shifts his focus from mending more fences to herding more cattle or vice versa, the PPF reflects the inherent tradeoff: dedicating more time to one activity leads to a reduction in the other. Each point on the PPF signifies a specific combination of fence-mending and cattle-herding activities that is feasible within the constraints of the cowboy's available time, highlighting the fundamental economic concept of opportunity cost and resource allocation.