Suppose you have 20 tomato plants and want to know if fertilizing them will help them produce more fruit. You randomly assign 10 of them to receive fertilizer and the remaining 10 to receive none. You otherwise treat the plants in an identical manner.
a. Explain whether this would be an observational study or a randomized experiment.
b. If the fertilized plants produce 30% more fruit than the unfertilized plants, can you conclude that the fertilizer caused the plants to produce more? Explain.