Answer: I'll give you quite a few.
Explanation:
Convenience sampling: (strengths) least expensive, least time consuming too. Most convenient.
(Weaknesses) selection bias. Not recommend by casual research.
Judgment sampling: (strengths) low cost, not time wasting. Convenient, ideal for exploratory research.
(Weaknesses) does not allow generalized subjective.
Snowball sampling: (strengths) can estimate rare characteristics.
(Weaknesses) time consuming.
Well some people think that the universe is faulty, empty and unstable, just like soap bubbles.
Hope this helps!
