In real life, you may sometimes have to deal with large numbers of discrete statistical data. For example, if you collect weight data of thirty different people, you may end up with a collection something like below:
25, 25.5, 27, 28, 29.5, 31, 32, 32.5, 37, 38,38.5, 39,39.5, 41, 44.5, 42, 46, 47.5, 48, 48.5, 50, 50.5, 51.5, 52.5, 53.5, 55.5, 56, 57, 59.5, 60
If you want to plot this kind of data graphically, you have to group the data and plot the data points falling in that group. You may group the data like below:
Weight (Kg) .........................Frequency
25-30 ..........................................5
30-35 ..........................................3
35-40 ..........................................5
40-45 ..........................................3
45-50 ..........................................4
50-55 ..........................................5
55-60 ..........................................4
Now plotting this kind of data you have to use histogram. The following three websites will help you create your histogram if you have your data ready.