There are two parts to this one. I actually plotted and created my own a table to organize the data to find the slope of the linear function. They call this function marginal propensity to consume.

from the book the table looks like this

year 1990 1997

total consumption(C) 3839 5494

National income(I) 6650 4215

my table is

year I C

1990 6650 3839

1997 4215 5494

I plotted I on the X axis and C on the Y.

I saw the line went from right to left meaning I should find a negative slope

I subtracted the change in both categories to come up with m= 1655/-2435 or -.67967.

That is the long answer to part b I believe.

Part a I am totally at a loss.

Find the formula for C as a function of I.

c(i) = i -c ? how does year get input into the formula? Been looking at this for days and still stuck.