The mode of a dataset is the data that happens most frequently. A dataset has more then one mode when the most frenquet data values happens the same number of times.
Let's put the dataset in ascending order:
[tex]18,12,19,15,19,18,6\to6,12,15,18,18,19,19[/tex]As we can see, most data happens once and 18 and 19 happens twice each. So, both are the modes.
Since the given one is 18, the second mode is 19.
