2.A researcher will conduct a study to investigate whether a certain eye drop is effective in relieving dry eyes. The researcher plans to obtain volunteers from the population of people with dry eyes. Randomly assign half of the people to a group to use the eye drop each day and half the people to a group to use a placebo each day. Observe the number of people who experience relief in each group after one week. a. Suppose the researcher wanted to guarantee a margin of error of no more than 0.04. What is the total number of volunteers required (both treatment groups) in order to guarantee a margin of error less than 0.04