It is calculated by adding up the data values (x), then dividing by the number of items (n).
The mean of a sample is traditionally labelled x-bar. The mean of a population is labelled µ (mu).
sum(x)/n = x-bar
For example, find the mean of the following sample dataset:
10
12
1
16
10
11
13
6
15
6
sum(x) = 10+12+1+16+10+11+13+6+15+6 =100
n=10
x-bar = 100/10 = 10
The mean is 10.
It is also the "center" of the data - in the sense that the difference of each value from the mean will sum up to zero. This is because there are equal positive differences as there are negative.Check this, using the above example:
10 - 10 = 0
12 - 10 = 2
1 - 10 = -9
16 - 10 = 6
10 - 10 = 0
11 - 10 = 1
13 - 10 = 3
6 - 10 = -4
15 - 10 = 5
6 - 10 = -4
0 + 2 + -9 + 6 + 0 + 1 + 3 + -4 + 5 + -4 = 0
The mean, median, and mode are all measures of central tendency. The skew can be determined by comparing these three measures.
