ANSWER
[tex]1.833[/tex]EXPLANATION
To find the z-score, we have to apply the formula:
[tex]Z=\frac{x-\mu}{\sigma}[/tex]where x = Score
μ = Mean
σ = Standard deviation
Therefore, the z-score for the test score is:
[tex]\begin{gathered} Z=\frac{86-75}{6} \\ Z=\frac{11}{6} \\ Z=1.833 \end{gathered}[/tex]