We want to find the mean, median, mode and range of the given data set. Let's start by sorting the given values.

4, 8, 12, 12, 16, 18, 21

Mean

The mean of a data set is calculated by finding the sum of all of the values in the set and then dividing by the number of values. In this case, there are

7

values.

Mean = \frac{Sum of values}{Number of values}

SubstituteValues

Substitute values

Mean = \frac{4 + 8 + 1 2 + 1 2 + 1 6 + 1 8 + 2 1}{7}

AddTerms

Add terms

Mean = \frac{9 1}{7}

CalcQuot

Calculate quotient

Mean = 13

The mean of the set is

13 .

Median

When the data are arranged in numerical order, the median is the middle value — or the mean of the two middle values — in a set of data. Let's arrange the given values and find the median.

4, 8, 12, 12, 16, 18, 21

The median of this set is

12 .

Mode

The mode is the value or values that appear most often in a set of data. Let's find the mode of the given values.

4, 8, 12, 12, 16, 18, 21

The value that appears most often is

12 .

Mode : 12

Range

The range is the difference between the greatest and least values in a set of data. For our exercise, the greatest value is

21

and the least value is

4 .

Range : 21 - 4 = 17

Exercise