Choosing an appropriate intervals is essential when constructing frequency distribution tables. Most frequency distribution tables have about 6 to 15 classes, equal class intervals, and the starting point of each class should be divisible by the class interval and each observation must fit in only one class. Therefore, in this case, a class interval of 5 points will be most appropriate, such that with a range of about 50 we get 10 classes, starting with a class of 25-30, and so on.
