Question

What are the minimum, first quartile, median, third quartile, and maximum of the data set?

9, 20, 4, 18, 4, 18, 20, 9

Answer 1

minimum 4
first quartile 9
median 9 & 18
third quartile 18
maximum 20

Answer 2

Minimum = 4

First quartile = 6.5

Median = 13.5

Third quartile = 19

Maximum = 20

Explanation:

1. Order the data set from the smallest to the largest number:

4 4 9 9 18 18 20 20

2. Find the minimum:

The minimum of the data set is the smallest number

Minimum = 4

3. Find the maximum:

The maximum of the data set is the largest number

Maximum = 20

4. Find the median:

As the data set has an even number of data, the median is the average between 9 and 18, that are the two data in the middle:

Median =
`(9+18)/(2)`

Median = 13.5

5. Find the first quartile:

The median divide the data set between two groups:

4 4 9 9 Median=13.5 18 18 20 20

The first quartile is the average of the two data in the middle of the first group:

4 4 9 9

First quartile =
`(4+9)/(2)`

First quartile = 6.5

6. Find the third quartile:

The third quartile is the average of the two data in the middel of the second group:

18 18 20 20

Third quartile =
`(18+20)/(2)`

Third quartile = 19