I don’t understand how to do this question please help me to understand

Explanation
The standart deviation is a measure that show us how dispersed the data is in relation to the mean.
Lets firts find the mean of this data set:
[tex]Mean=\frac{27+19+26+31+12}{5}=\frac{115}{5}=23[/tex]And for the standart deviation:
[tex]\begin{gathered} S=\sqrt{\frac{(27-23)^2+(19-23)^2+(26-23)^2+(31-23)^2+(12-23)^2\text{ }}{5}} \\ S=\sqrt{\frac{226}{5}} \\ S\approx6.72 \end{gathered}[/tex]Answer
6.72