Mean : The average of all the data in a set.
Median : The value in a set which is most close to the middle of a range.
Mode : The value which occures most frequently in a data set.
12,9,12,11,10,18,7,19,13,19
Mean = 13 (Average)
Median = 12 (Middle)
Mode = 12, 19 (most common)