Given,

\(\displaystyle\mu={72}\)

\(\displaystyle\sigma={15}\)

a)

The standard scores (z-values) of students receiving the grade of 65 is,

\(\displaystyle{z}={\frac{{{x}-\mu}}{{\sigma}}}\)

\(\displaystyle={\frac{{{65}-{72}}}{{{15}}}}\)

=-0.47

\(\displaystyle\mu={72}\)

\(\displaystyle\sigma={15}\)

a)

The standard scores (z-values) of students receiving the grade of 65 is,

\(\displaystyle{z}={\frac{{{x}-\mu}}{{\sigma}}}\)

\(\displaystyle={\frac{{{65}-{72}}}{{{15}}}}\)

=-0.47