US Federal Debt Each Year 1930-2020 Years Since 1930 Federal Debt (in billion $) ... 0 16 30 271 81 10,025 90 20,245 a. Clearly explain the meaning, including units of the ordered pair (81, 10025). b. Find the ARC for the two intervals given below and include units on your answer. Then describe what THOSE VALUES tell us about the appropriateness of using a linear model for this data. First interval: 1960 to 2011 Second interval: 2011 to 2020 Appropriateness of a linear model and why