The Following Frequency Distribution Presents the Weights in Pounds (Lb)

Multiple Choice

The following frequency distribution presents the weights in pounds (lb) of a sample of visitors to a health clinic.
$\begin{array}{cc}\hline \text { Weight (lb) } & \text { Frequency } \\\hline 90-99 & 1 \\100-109 & 4 \\110-119 & 4 \\120-129 & 3 \\130-139 & 7 \\140-149 & 6 \\150-159 & 4 \\160-169 & 2 \\\hline\end{array}$ What is the class width?

A) 11
B) 80
C) 10
D) 9