Premise:
"A recent report of the National Academy of Sciences (NAS) concluded that while most Americans face a very low risk from methylmercury, children of women who consume large amounts of fish during pregnancy face a much higher risk."
Hypothesis: Methylmercury is a risk for children of pregnant women that consume high amounts of fish.

yes

Premise:
"The guide does not address all of the responsibilities which fall to federal agency CIOs - only those which have parallels in the private sector."
Hypothesis: The guide was overwhelming with too much information about the duties.

no

Premise:
"The Merchant said, peevishly, "Why do you keep silence?""
Hypothesis: The Merchant was annoyed when he didn't get an answer.
it is not possible to tell