To answer this question we will use the following formula to compute the z-score:
[tex]\begin{gathered} z=\frac{x-\mu}{\sigma}, \\ \text{where x is the observed value, }\mu\text{ is the mean, and }\sigma\text{ is the standard deviation.} \end{gathered}[/tex]Substituting x=19min, μ=16min, and σ=2.1min we get:
[tex]z=\frac{19\min -16\min }{2.1\min }\text{.}[/tex]Simplifying the above result we get:
[tex]z=\frac{3}{2.1}=\frac{10}{7}\approx1.43.[/tex]Answer: 1.43.
