Question

A graduate student believes that people consider faces with more contrast between eye color and skin tone as more feminine. He identifies the null and alternative hypotheses as:

Answer 1

Null hypothesis is basically: there is no difference between two characteristics.
So in this case H(0) or null hypothesis is:
No difference in femininity based on contrast between eye color and skin tone.
Alternative hypothesis or H(a) basically contradicts that, so in this case:
There is observed difference in femininity based on contrast between eye color and skin tone.