Answer:
0.647
Step-by-step explanation:
The z-score of a variable, [tex]x[/tex], is given by
[tex]z = \dfrac{x-\mu}{\sigma}[/tex]
where [tex]\mu[/tex] is the mean and [tex]\sigma[/tex] is the standard deviation.
For a bluefish, [tex]\mu=288[/tex] and [tex]\sigma = 51[/tex]. The z-score for [tex]x=321[/tex] is
[tex]z = \dfrac{321-288}{51}=\dfrac{33}{51} = 0.647[/tex]