$\"\"$

(a).

From the table of data, starting from $\"\"$ to $\"\"$ the following graph is obtained by the

regression method.

$\"\"$

By using the regression capabilities of the excel sheet: $\"\"$ .

Where $\"\"$ is number of years calculated from $\"\"$ .

$\"\"$

(b)

In year $\"\"$ the amount of the federal debt is calculated by substituting $\"\"$ in the obtained equation.

$\"\"$

Therefore, the amount of the federal debt in year $\"\"$ is $\"\"$ .

$\"\"$

(a).

$\"\"$

(b).

The amount of the federal debt in year $\"\"$ is $\"\"$ .