Points P and Q are graphed below. Which is the best approximation of the distance between points P and Q? A. 6.8
B. 7.2
C. 8.3
D. 9.2

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.