Mean, Mode, Median & Range.

- Mean -

The mean is the average of the numbers: a calculated "central" value of a set of numbers. To calculate: Just add up all the numbers, then divide by how many numbers there are. Pros: useful for comparing sets of data. Cons: The mean has a tendency to be pulled toward extreme values. -

- Mode -

The number which appears most often in a set of numbers. Example: in (6, 3, 9, 6, 6, 5, 9, 3) the Mode is 6 (it occurs most often). Pros: outliers do not affect the mode. - Cons:  may not be one distict answer, there may be more than one mode in a set (or no mode in a set). -

- median -

The difference between the lowest and highest values. In {4, 6, 9, 3, 7} the lowest value is 3, and the highest is 9, so the range is 9-3 = 6. - Pros; useful for comparing sets of data. Cons; not as popular (or used as often) as the mean.

- range -

The difference between the lowest and highest values. In {4, 6, 9, 3, 7} the lowest value is 3, and the highest is 9, so the range is 9-3 = 6. Pros; Smaller numbers are an average. Cons; massive numbers stand out.