It describes a whole set of data with a single value that represents the centre of its distribution.
There are three main measures of central tendency: the mode, the median and the mean.
Mean
It is the sum of the observations divided by the sample size.
The mean of the values 5,6,6,8,9,9,9,9,10,10 is (5+6+6+8+9+9+9+9+10+10)/10 = 8.1
Limitation :
It is affected by extreme values. Very large or very small numbers can distort the answer
Median
It is the middle value. It splits the data in half. Half of the data are above the median; half of the data are below the median.
Advantage : It is NOT affected by extreme values. Very large or very small numbers does not affect it
Mode
It is the value that occurs most frequently in a dataset
Advantage : It can be used when the data is not numerical.
Disadvantage :
1. There may be no mode at all if none of the data is the same
2. There may be more than one mode