A farmer 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?

Experimental

Explanation:

Experimental study is the study in which researcher has some control over the variables where he can experiment and test over the groups. Observational study provides no control to researcher .He can only observe the process.

According to the question, study conducted by farmer is experimental as farmer has the control over quantity variable of land , grouping choice of crop etc.He is dividing  the land equally in four parts,sowing same crops into 4 groups in each piece depicts that he is testing or experimenting everything equally.

explanation:

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the answer is:

c. economic output