For each of the following cases [(a), (b), and (c)], (I) state whether the study should be observational or

experimental. (II) state whether the study should be run blind, doubleblind, or neither. If the study should be run blind or double-blind, who should be blinded?

(a) An investigation of whether taking aspirin reduces one's chance of having a heart attack.

(b) An investigation of whether babies born into poor families (family income below $25,000) are more likely to weigh less than 5.5 pounds at birth than babies born into wealthy families (family income above $65,000).