Explanation
Given that
[tex]\begin{gathered} z=-4.80 \\ x=23.55 \\ \mu=32.67 \end{gathered}[/tex]Using the z-score formula;
[tex]\begin{gathered} z=\frac{x-\mu}{\sigma} \\ -4.80=\frac{23.55-32.67}{\sigma} \\ -4.80\sigma=-9.12 \\ \sigma=\frac{-9.12}{-4.80} \\ \sigma=1.9 \end{gathered}[/tex]Answer: 1.9