Afarmer divided his piece of land into 4 equivalent groups. the quality of the soil is the same across the 4 groups of land. he planted the same crop in all 4 groups of land and recorded the yield of the crop in all 4 groups for a 4 week period. is the study observational or experimental? if it is an experiment, what is the controlled factor?

Two assets have the following expected returns and standard deviations when the risk-free rate is 5%: asset a e(ra) = 18.5% σa = 20% asset b e(rb) = 15% σb = 27% an investor with a risk aversion of a = 3 would find that on a risk-return basis. a. only asset a is acceptable b. only asset b is acceptable c. neither asset a nor asset b is acceptable d. both asset a and asset b are acceptable