The z-score can be calculated by the following formula:
[tex]z=\frac{x-m}{\sigma}[/tex]Where m is the mean, σ is the standard deviation and x is the actual score.
By replacing John's result (83) for x, 79 for m and 3.5 for σ, we get:
[tex]z=\frac{83-79}{3.5}=1.14[/tex]Similarly, for Jane's result on test B:
[tex]z=\frac{80-77}{2.5}=1.2[/tex]John's z-score was 1.14 and Jane's z-score was 1.2, then, Jane did better than John
