The numbers of hours worked (per week) by 400 statistics students are shown below. $$\begin{array} { l l }
\text { Number of hours } & \text { Frequency } \
0 - 9 & 20 \
10 - 19 & 80 \
20 - 29 & 200 \
30 - 39 & 100
\end{array}$$ The class width used in this frequency distribution is
A) 4.5.
B) 9.
C) 10.
D) 39.

Question

The numbers of hours worked (per week) by 400 statistics students are shown below. $$\begin{array} { l l } 
\text { Number of hours } & \text { Frequency } \
0 - 9 & 20 \
10 - 19 & 80 \
20 - 29 & 200 \
30 - 39 & 100
\end{array}$$   The class width used in this frequency distribution is
A) 4.5.
B) 9.
C) 10.
D) 39.

Quizplus · Accepted Answer

The class width is the difference between the upper and lower boundaries of any class interval. Here, each class interval spans 10 units (e.g., 0-9, 10-19, etc.).