Data was collected for 318 randomly selected 10 minute intervals. For each ten-minute interval, the number of people entering the atrium of a large mall were recorded. The data is summarized in the table below.

Question

Number
of Guests Frequency
160 – 179 59
180 – 199 59
200 – 219 39
220 – 239 64
240 – 259 97

What is the class width for this GFDT?

Class width =

Answer 1

To find the class width for a grouped frequency distribution table (GFDT), you can use the formula:

\[ \text{Class Width} = \text{Upper Limit of Class} - \text{Lower Limit of Class} + 1 \]

For the classes provided in the table:

• For the class 160 – 179:
  • Lower Limit = 160
  • Upper Limit = 179

So the class width would be calculated as:

\[ \text{Class Width} = 179 - 160 + 1 = 20 \]

To confirm, we can check the other classes:

• For the class 180 – 199: \( 199 - 180 + 1 = 20 \)
• For the class 200 – 219: \( 219 - 200 + 1 = 20 \)
• For the class 220 – 239: \( 239 - 220 + 1 = 20 \)
• For the class 240 – 259: \( 259 - 240 + 1 = 20 \)

Each class has a width of 20.

Thus, the class width is:

\[ \text{Class width} = 20 \]