Question

Two students, John and Ali, from different high schools, wanted to find out who had the highest GPA when compared to his school. Which student had the highest GPA when compared to his school?

Short answer

John has the better GPA as compared to Ali in his school.

Step-by-step solution

Content Introduction

For both students determine the standard deviations his GPA is away from the average of his school.

$$\begin{gathered} s_{x}ofGPA=\frac{value-mean}{s\tan darddeviation} \\ {s}_x=\frac{x-\mu }{\delta } \end{gathered}$$

Content Explanation

For John, standard deviation is

$$\begin{gathered} s_x=\frac{x-\mu }{\delta } \\ {s}_x=\frac{2.85-3.0}{0.7} \\ {s}_x=-0.21 \end{gathered}$$

For Ali, standard deviation

$$\begin{gathered} s_x=\frac{x-\mu }{\delta } \\ {s}_x=\frac{77.80}{10} \\ {s}_x=-0.3 \end{gathered}$$

Conclusion

John's score of $-0.21$is higher than Ali's score $-0.3$.For GPA higher values are better, so we conclude that John's GPA is better.