What is the cumulative frequency for the last class interval?

The cumulative frequency for the last class interval is the total number of data points in the dataset.

In statistics, cumulative frequency is the running total of frequencies through the classes in a frequency distribution. To find the cumulative frequency for the last class interval, you simply add up all the frequencies from each class interval up to and including the last one. This gives you the total number of data points in the entire dataset.

For example, if you have a frequency table with class intervals and their corresponding frequencies, you start by adding the frequency of the first class interval to the frequency of the second class interval. Then, you add this sum to the frequency of the third class interval, and so on, until you reach the last class interval. The cumulative frequency for the last class interval will be the sum of all the frequencies in the table.

Let's say you have the following frequency table:

| Class Interval | Frequency |
|----------------|-----------|
| 0-10 | 5 |
| 10-20 | 7 |
| 20-30 | 3 |
| 30-40 | 10 |

To find the cumulative frequency for the last class interval (30-40), you add up all the frequencies: 5 (0-10) + 7 (10-20) + 3 (20-30) + 10 (30-40) = 25. Therefore, the cumulative frequency for the last class interval is 25, which means there are 25 data points in total.