Athletes performing in bright sunlight often smear black eye grease under their eyes to reduce glare. Does eye grease work? In one study, 16 student subjects took a test of sensitivity to contrast after 3 hours facing into bright sun, both with and without eye grease. This is a matched pairs design. Here are the differences in sensitivity, with eye grease minus without eye grease: 0.07 0.64 -0.12 -0.5 -0.18 -0.14 -0.16 -0.03

0.05 0.02 0.43 0.24 -0.11 0.28 0.05 0.29

Requried:
What are the null and alternative hypotheses?