Histograms are a type of bar plot for numeric data that group the data into bins.
A histogram is a graphical representation of data that comprises a series of contiguous columns (i.e., there is no gap between them).
It differs from a bar graph, in the sense that a bar graph relates two variables, but a histogram relates only one.
How to use it:
Select the value you want to measure the frequency of
Choose the number of bins
The height of each bars correspond to the frequency of observations that fall within the range of values covered by each bins. The more bins, the less values are grouped in each.
This first histogram has 8 bins:
The following histogram shows the same data, but with 25 bins: