Answer
a. please see image
b. exponential
Work Step by Step
Use the table to plot points of the scatter plot.
Comparing this scatter plot with Figure 4.24,
(page 499, just before example 4),
its pattern resembles
the linear (2nd from the right)
and the exponential model (first on the left)
We note that for the same increment in age (5 years),
the "savings needed" rise by a greater amount as we move to the right...
(the slope gets steeper as x gets greater)
which is why we choose the exponential model over the linear.
Best choice: exponential function
