Answer
a. Average ticket price: ${{\$}} 3.47$, which is an understimate of the value in the graph by ${{\$}} 0.08.$
b. Average ticket price: ${{\$}} 6.47$, which is an overestimate of the value in the graph by ${{\$}} 0.06.$
Work Step by Step
$a.$
In $1985$, ($5$ years after 1980), $ n=5.$
Substituting into the formula,
$T=0.15(5)+2.72$
$=0.75+2.72$
$=3.47$
The graph reads a value of $3.55$, so the model underestimates the graph by $0.08$
$(3.55-3.47=0.08)$
$b.$
In $2005$, ($25$ years after 1980), $ n=30.$
Substituting into the formula,
$T=0.15(25)+2.72$
$=3.75+2.72$
$=6.47$
The graph reads a value of $6.41$, so the model overestimates the graph by $0.06$
$(6.47-6.41=0.06)$
