Premise:
"There are good swimming beaches on the Princes' Islands, too, but they get extremely crowded at weekends."
Hypothesis: Prince Islands tend to get crowded during the weekday.

no

Premise:
"Not entirely unmarried men are seldom worth the trouble."
Hypothesis: Unmarried men are not worth the trouble.

yes

Premise:
"While consumer activists pump for another technological fix--smart air bags that can adjust their behavior to the stature of front-seat passengers--more and more of us (perhaps influenced in part by mandatory seat-belt laws in 49 states) are squandering those 2.97 precious seconds and buckling up."
Hypothesis: Instead of trying to develop new air bag technology we're buckling our seat belts.
yes