Answer:
-2.14
Explanation:
The z-score for a given value can be calculated as
[tex]z-score=\frac{value\text{ - mean}}{\text{ standard deviation}}[/tex]Therefore, the z-score of 51 can be calculated as
[tex]\begin{gathered} \text{ z-score =}\frac{51-66}{7} \\ \\ \text{ z-score=}\frac{-15}{7} \\ \\ \text{ z-score=-2.14} \end{gathered}[/tex]Therefore, the answer is -2.14
