The Mean, Median and Mode are the arithmetic average of a data set. This is found by adding the numbers in a data set and dividing by how many numbers there are. The median is the middle number in a data set when the numbers are listed in either ascending or descending order. The mode is the value that occurs the most often in a data set, and the range is the difference between the highest and lowest values in a data set.

The Mean:

Here,
∑$\sum$ represents the summation
X represents scores
N represents number of scores.

The Median:

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

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

The Mode:

Question: Find the mean, median, mode, and range for the following list of values: 13, 18, 13, 14, 13, 16, 14, 21, 13

Solution:

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

The mean is the usual average, so:

13+18+13+14+13+16+14+21+139=15$\frac{13+18+13+14+13+16+14+21+13}{9}=15$

Note that the mean isn’t 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 order:

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

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

9+12=102=5$\frac{9+1}{2}=\frac{10}{2}=5$

= 5th number, So 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
range: 8