Cohen wanted to know how much his backpack weighed with all of his homework in it. He used the metric scale in the science room and saw that his backpack weighed 6,000 grams. How many kilograms did his backpack weigh?

The major difference is that a histogram is only used to plot the frequency of score occurrences in a continuous data set that has been divided into classes, called bins.  bar charts, on the other hand, can be used for a great deal of other types ofvariables  including  ordinal  andnominal  data sets.