Simplest form of 9 feet:4 yards simplest form of 5 gallons:8 quarts
simplest form of 800 centimeters:2 meters
options for answers: 5:8, 4:1, 4:9, 3:4, 5:2, 3:1

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.