To determine the frequency of the class containing the value 26 based on the histogram provided, let's examine the histogram's data intervals and corresponding frequencies:

1. The intervals shown are labeled on the x-axis: $1, 7, 13, 19, 25, 31, 37$, which suggests that each class likely spans between these values.

2. The value 26 falls within the interval 25–31.

3. Observing the histogram's bar for this interval, the bar's height represents a frequency of 8.

Thus, the frequency of the class containing the value 26 is 8.

Would you like more details on how to interpret histograms? Here are a few questions you might find helpful:

1. How can we identify the interval ranges from the x-axis labels?
2. What are the common mistakes when interpreting histogram frequencies?
3. How can histograms be used to summarize large data sets?
4. What is the difference between a histogram and a bar chart?
5. How can we determine the mode of the dataset from a histogram?

Tip: Always check the axis labels and intervals in a histogram to ensure accurate interpretation of data frequencies.