Chapter 1.5, Problem 23E

BOUNCED-CHECK CHARGES Overdraft fees have become an important piece of a bank’s total fee income. The following table gives the bank revenue from overdraft fees (in billions of dollars) from $2004$ to $2009$. Here, $x=4$ corresponds to $2004$.

Year, $x$	$4$	$5$	$6$	$7$	$8$	$9$
Revenue, $y$	$27.5$	$29$	$31$	$34$	$36$	$38$

a. Find an equation of the least squares line for these data.

b. Use the result of part (a) to estimate the average rate of increase in overdraft fees over the period under consideration.

c. Assuming that the trend continued, what was the revenue from overdraft fees in $2011$.

Source: New York times