A histogram is used to display the frequency of measurements, the distribution of measurements and how well measurements may or may not be centered around the nominal.
A histogram consists of tabular frequencies, shown as adjacent rectangles, erected over discrete intervals with an area equal to the frequency of the observations in the interval. The height of a rectangle is also equal to the frequency density of the interval, i.e., the frequency divided by the width of the interval. The total area of the histogram is equal to the number of data.
The chart is created using every individual value recorded in each subgroup.