Question

The scatterplot shows number of manatees from 1991 to 2011. The best fit line is drawn for the plot. Find the value closest to the average yearly increase in the number of manatees.

• A. $0.75$
• B. $75$
• C. $150$
• D. $750$

Answer 1

The correct option is C $150$

$\Rightarrow$ The slope of the line of best fit is the value of the average increase in manatees per year.

$\Rightarrow$ Using approximate values found along the line of best fit

$\Rightarrow$ $1,200$ manatees in $1991$ and $4,200$ manatees in $2011$

The approximate slope $=\frac{4200-1200}{2011-1991}=\frac{3000}{20}=150$

$\therefore$ The value closest to the average yearly increase in the number of manatees Is $150$.