What is the definition of average …

The mean is often called the average. To find the mean you take a set of data and calculate the sum of the data, after that you divide the sum by the number of pieces in the set.

The Median

If the total number of observations (n) is an odd number, then the formula is given below:

Median=(n+1)th/ 2 observation

If the total number of the observations (n) is an even number, then the formula is given below:

Median =(n/2)th observation+(n/2 + 1)the observation 

The mode is the most frequently occuring observation or value.

 Find the mean, median, mode, and range for the following list of values:

13, 18, 13, 14, 13, 16, 14, 21, 13

Solution:

Given data: 13, 18, 13, 14, 13, 16, 14, 21, 13

The mean is the usual average.

Mean = (13+18+13+14+13+16+14+21+13)/ 9=15

(Note that the mean is not a value from the original list. This is a common result. You should not assume that your mean will be one of your original numbers.)

The median is the middle value, so to rewrite the list in ascending order as given below:

13, 13, 13, 13, 14, 14, 16, 18, 21

There are nine numbers in the list, so the middle one will be

(9+1)/ 2=10/2=5

= 5th number

Hence, the median is 14.

The mode is the number that is repeated more often than any other, so 13 is the mode.
The largest value in the list is 21, and the smallest is 13, so the range is 21 – 13 = 8.

Mean = 15
Median = 14
Mode = 13