In some science experiments, you are trying to compare the effects that a certain variable may have on the topic of interest. For example, read the following question: What brand of fertilizer makes roses grow the fastest? Let’s say you had three brands that you were using, and we will just call them brands A, B, and C. In an experiment, the different types of fertilizer would be called treatments, because you will be treating roses with each type of fertilizer. Most experiments that have a treatment also have a control, which in this case would be roses that had no fertilizer applied to them. In any experiment you want to eliminate as many variables as possible. In this experiment, the only thing you want to vary is the type of fertilizer. Everything else (sunlight, water, temperature, etc) you hope, will stay the same. Use the information about this example experiment to answer problems 7-10. How many different groups of roses will you need?
Choose one answer.
a. Three
b. Four