Mean
The mean is the average. Add all values and divide by the number of values.
Example: data 2, 4, 4, 6, 9. The mean is (2+4+4+6+9)/5 = 5.
Median
The median is the middle value when data is ordered.
Mode
The mode is the value that appears most often. In 2, 4, 4, 6, 9 the mode is 4.