Explanation:
The original table (attached to this response) shows single values as classes.
To construct a new frequency distribution for this data with 4 classes, follow these steps:
i. Starting from the least value (which is 10) create groups each of 4 values. For example, the first group will contain 10, 11, 12 and 13. Therefore, we have a class of 10 - 13.
The second group will contain 14, 15, 16 and 17. Therefore, we have a class of 14 - 17
The third group will contain 18, 19, 20 and 21. Therefore, we have a class of 18 - 21
ii. Get the frequency of these classes, we add the frequencies of the members of the class.
For example,
Class 10 - 13 will have a frequency of (1 + 3 + 7 + 18) = 29
Class 14 - 17 will have a frequency of (10 + 4 + 2 + 7) = 23
Class 18 - 21 will have a frequency of (16 + 10 + 6 + 2) = 34
The new table has been attached to this response.