Question

Determine whether each experiment described below is observational or​ designed, and explain your reasoning.

B ucouTICIP Determine whether each experiment described below is observational or designed, and explain your reasoning. a. A farmer uses pesticide on all her crops for one full year, and no pesticide the next, and then compares her net income for both years in order to determine whether the pesticide is worth its price. O A. An observational experiment because the analyst simply observes the treatments and the response on a sample of experimental units OB. A designed experiment because the analyst controls the specification of the treatments and the method of assigning the experimental units to a treatment OC. A designed experiment because the analyst simply observes the treatments and the responses on a sample of experimental units OD. An observational experiment because the analyst controls the specification of the treatments and the method of assigning the experimental units to a treatment b. A high school statistics teacher reviews the test scores of all the students taught throughout the semester, grouped into the time of day they were taught, in order to determine whether the time of the day affects retention. O A. An observational experiment because the analyst simply observes the treatments and the response on a sample of experimental units OB. A designed experiment because the analyst controls the specification of the treatments and the method of assigning the experimental units to a treatment OC. An observational experiment because the analyst controls the specification of the treatments and the method of assigning the experimental units to a treatment OD. A designed experiment because the analyst simply observes the treatments and the responses on a sample of experimental units Click to select your answer.

Answer 1

a) The correct option is B because as in a designed study, the farmer controls the treatment applied on the sample of study, crops in this case. Rather than just observing the response, the farmer changes the treatment applied on crops in different years to study the effect on the response variable, yearly net income.

b) The correct option is A. This is an observational experiment, because the statistics teacher simply compares the students' test scores depending upon the time of the day when the students were taught, and does not impact the treatment to the participants (quality of teaching imparted or time of day for teaching particular students) in this process.