The problem is asking to determine the class width for a histogram where the number of people entering the atrium of a large mall has been recorded. From the histogram image, we can extract the necessary information to compute the class width.

Here's how you can solve the problem step-by-step:

1. Class Limits Observation: From the histogram, the class intervals for the number of people appear to be:

   • 45–50
   • 50–55
   • 55–60
   • 60–65

2. Class Width Calculation: The class width is the difference between the lower limit of one class and the lower limit of the next class. For instance: $\text{Class Width} = 50 - 45 = 5$

Therefore, the class width is 5.

Would you like more details, or do you have any questions?

Here are five related questions to consider:

1. What is the total number of intervals used in this histogram?
2. How can you calculate the frequency density for each class in a histogram?
3. Why is the class width important in constructing a histogram?
4. What is the difference between class limits and class boundaries?
5. How can the histogram be used to estimate the mean number of people entering the atrium?

Tip: When analyzing histograms, always check that the class intervals are consistent, as this affects the shape and interpretation of the data distribution.