#### Answer

The number of calories needed between the age of 19 and 30 are $2332$. It underestimates the number shown by the graph by $68$calories.

#### Work Step by Step

Consider the equation as follows:
$M=-96{{x}^{2}}+802x+660$
where M represents the number of males and x represents the age group.
Now, substitute the value of $x$as 4 and find the value of$F$.
$\begin{align}
& M=-96{{x}^{2}}+802x+660 \\
& =-96{{\left( 4 \right)}^{2}}+802\left( 4 \right)+660 \\
& =-1536+3208+660 \\
& =2332
\end{align}$
Here, x is considered as 4 because the age group 19-30 lies in the group 4.
From the graph, $2400$calories are needed for males of age group, 19-30.
Now, subtract the value of the calorie against age range 19-30 given in the graph from the calculated value of the calorie to obtain:
$2400-2332=68$
The value of graph is higher by 68 calories.
Hence, the given model underestimates the number shown by the graph by $68$ calories.