Question

question 12. lindsay wants to study the effect of a new fertilizer on her plants. she randomly selects half her plants to receive the fertilizer and observes how tall they grow over the next three months. this is an example of a. a random phenomenon b. an experiment c. a sample survey d. an observational study.

Explanation:

• Option A: A random phenomenon refers to an event with uncertain outcomes, but this scenario involves a controlled action (applying fertilizer) to study its effect, not just a random event. So A is incorrect.
• Option B: An experiment involves manipulating a variable (here, applying the new fertilizer to a randomly selected group of plants) to observe the effect (plant growth). The random selection of plants to receive the fertilizer and the manipulation of the fertilizer application fit the definition of an experiment.
• Option C: A sample survey involves collecting data from a sample through questioning or observation without manipulating variables. Here, the fertilizer is applied (a manipulation), so it's not a survey. Thus C is incorrect.
• Option D: An observational study involves observing without manipulating variables. Since the fertilizer is applied (a manipulation), this is not an observational study. So D is incorrect.

Answer:

B. an experiment