In a frequency distribution, class mark of a class is 25 and the lower boundary of the class is 9. Find the class length.
In a frequency distribution table with 12 classes,the class-width is 2.5 and the lowest class boundary is 8.1,then what is the upper class boundary of the highest class?
The width of each of nine classes in a frequency distribution is 2.5 and the lower class boundary of the lowest class 10.6. Then the upper-class boundary of the highest class is