3. (12 points) You plan to conduct a random sample of students on campus about whether they prefer Mac or Windows laptops. Let p be the true proportion of students who prefer Mac laptops, and let it be the sample proportion who prefer Mac laptops. 3.1. If p = 0.2 and you sample 200 students, what is sd()? 3.2. If p = 0.5 and you sample 200 students, what is sd()? 3.3. If p = 0.8 and you sample 200 students, what is sd()? 3. 4. If you wanted to estimate a condence interval with a margin of error of 4 percentage points, would the necessary sample size be largest if p is small, moderate, or large