Answer
Zandra did better in relation to her gender.
Work Step by Step
$z=\frac{x-μ}{σ}$
Roberto:
$z=\frac{63.2-69.4}{8.9}=-0.697$
Zandra:
$z=\frac{79.3-84.7}{7.4}=-0.730$
Zandra did better in relation to her gender. Her z-score is more negative than Roberto's z-score.
