According to Article 1 of the Constitution, how many representatives there are in Congress is determined by each state's population. A census is taken every 10 years to accurately apportion a state's representatives. The most basic calculation is there is to be one representative for every 30,000 residents. If there are not 30,000 people living in a state, that state will still get at least one representative.
Find the Class Width of the Frequency Table. The lower limit for every class is the smallest value in that class. On the other hand, the upper limit for every class is the greatest value in that class. The class width is the difference between the upper or lower class limits of consecutive classes. All classes should have the same class width. In this case, class width equals to the difference between the lower limits of the first two classes. Simplify to find that the class width is .
Round this value up so that the class width has the same precision (number of significant digits) as the measurements. So if we are measuring body weights of black bears and the smallest weight is 16.0 kg and the largest weight is 118 kg, and we wish to use 10 classes, then the class width is 10.2 kg.