Answer
\begin{array}{c}& \textbf{Watts per Hour} & \textbf{Frequency}
\\\hline & \text{465-473} & \text{9}
\\ & \text{474-482} & \text{7}
\\ & \text{483-491} & \text{7}
\\ & \text{492-500} & \text{6}
\\ & \text{501-509} & \text{7}
\\ & \text{510-518} & \text{4}
\end{array}
Work Step by Step
Find the width of each class by subtracting the lowest value from the highest. Divide the difference by 6, as 6 classes were specified in the instructions. Round up to determine the width.
$\frac{514-465}{6}=\frac{49}{6}=8.1\overline6$
Round up to 9.
The lowest value is 465. Add 9 to each lower limit to find the next lower limit in the table. The upper limit will be one less than the lower limit that follows.
$465+9=474$
$474+9=483$
$483+9=492$
$492+9=501$
$501+9=510$
$510+9=519$ (Computed only to find the final upper limit)
