DEFINITIONS
A boxplot is a way to show the spread and centers of a data set.
The box and whiskers chart shows you how your data is spread out. Five pieces of information (the “five-number summary“) are generally included in the chart:
1) The minimum (the smallest number in the data set). The minimum is shown at the far left of the chart, at the end of the left “whisker.”
2) First quartile, Q1, is the far left of the box (or the far right of the left whisker).
3) The median is shown as a line in the center of the box.
4) Third quartile, Q3, shown at the far right of the box (at the far left of the right whisker).
5) The maximum (the largest number in the data set), is shown at the far right of the box.
SOLUTION
From the data set given, we have the following information:
1) Minimum Value: 1
2) First Quartile: The position for the first quartile is given by the formula
[tex]\Rightarrow\frac{n+1}{4}[/tex]
where n is the number of data.
In the problem, there are 14 data values. Therefore, the position is:
[tex]\Rightarrow\frac{14+1}{4}=3.75th\text{ position}[/tex]
Using the 3.75th position, we have
[tex]\begin{gathered} 3rd\Rightarrow2 \\ 4th\Rightarrow2 \\ \therefore \\ Q1=2 \end{gathered}[/tex]
3) Median: The median position is given by the formula
[tex]\Rightarrow\frac{n+1}{2}[/tex]
Therefore, the median position will be:
[tex]\Rightarrow\frac{14+1}{2}=\frac{15}{2}=7.5th\text{ position}[/tex]
The 7.5th position will give:
[tex]\begin{gathered} 7th\Rightarrow11 \\ 8th\Rightarrow11 \\ \therefore \\ Med=11 \end{gathered}[/tex]
4) Third Quartile: The third quartile's position is gotten using the formula:
[tex]\Rightarrow\frac{3}{4}(n+1)_{}[/tex]
Therefore, the Q3 position will be:
[tex]\Rightarrow\frac{3}{4}\times15=11.25th\text{ position}[/tex]
Therefore, the 11.25th position will give:
[tex]\begin{gathered} 11th\Rightarrow14 \\ 12th\Rightarrow16 \\ \therefore \\ Q3=14(0.75)+16(0.25)=14.5 \end{gathered}[/tex]
5) Maximum: 19
Therefore, the boxplot is shown below:
