SAT Math Practice Question

In order to determine if treatment $\mathrm{X}$ is successful in improving eyesight, a research study was conducted. From a large population of people with poor eyesight, 300 participants were selected at random. Half of the participants were randomly assigned to receive treatment $X$, and the other half did not receive treatment $X$. The resulting data showed that participants who received treatment $X$ had significantly improved eyesight as compared to those who did not receive treatment $X$. Based on the design and results of the study, which of the following is an appropriate conclusion?

1. A.Treatment $\mathrm{X}$ is likely to improve the eyesight of people who have poor eyesight.
2. B.Treatment $\mathrm{X}$ improves eyesight better than all other available treatments.
3. C.Treatment $X$ will improve the eyesight of anyone who takes it.
4. D.Treatment $\mathrm{X}$ will cause a substantial improvement in eyesight.