Answer:
Brian's z-score is 2.4
Step-by-step explanation:
The equation for z score is presented as follows;
[tex]z = \frac{x- \mu}{\sigma}[/tex]
Where:
x = Score = 80%
μ = Mean = 68%
σ = Standard deviation = 5%
Plugging in the values gives;
[tex]z = \frac{80- 68}{5} =2.4[/tex]
Therefore, Brian's z-score on the Chemistry Exam, where the mean is 68%, the standard deviation is 5% and Brian's score is 80% = 2.4.