Answer
Domain: $0\leq \mathrm{t}\leq 20.$
The domain $\mathrm{t}\leq 20$ is inappropriate, because it assumes that t can be negative, which does not makes sense in this case.
Work Step by Step
From 1983 to 2003, there are 20 years.
So, an appropriate domain would be $0\leq \mathrm{t}\leq 20.$
The domain $\mathrm{t}\leq 20$ is inappropriate, because it assumes that t can be negative,
which does not makes sense in this case.
