Julie wanted to show this information to her Area Manager, but didn't feel that she could use the tally chart itself (it was a bit messy after 2 weeks on the stockroom wall). So, she decided to construct a graph from the data.
She could have used a run chart to show the number of shoes that were sold on each day. However, she decided it would be more useful to find out which sizes had sold best, and for this she chose to use a histogram.
A histogram is a type of graph which uses blocks or bars to represent the frequencies for a set of values. Generally, the possible values are added to the horizontal axis and the frequency goes on the vertical axis. In this case, the possible values are the shoe sizes from 3 to 8.