Question

the mean grade in physics examination was 75 and the standard deviation was 5. Determine the grade of the student whose standard is -0.5

Answer 1

$\mu=75 \\ \sigma=5$

Standard score z = -0.5

$z = \frac{x- \mu}{\sigma} \\ -0.5 = \frac{x -75}{5} \\ -2.5 = x -75 \\ x = 75-25 = 50$

Answer: 50