The president of State U requests a study be done to assess the effectiveness of posting timely information such as school closings, schedule changes, etc. on the university’s web site. In a randomly selected sample of 200 students, 48 responded that they checked the site on a regular basis (at least twice a school week). (a) Estimate the true proportion of students that check the site on a regular basis with 90% confidence. (b) Explain the meaning of "90% confident." (c) What is the margin of error associated with your estimate? How do we interpret this value? (d) The marketing director, not having seen the results of the study, told the president he felt at least 30% of State U students check the web site regularly. What does the interval suggest about his claim? (e) Suppose the president wanted a margin of error of 3% at 95% confidence. How many students should the school have used in its study? Do not assume previous data exist. Provide the most conservative estimate of the sample size. (f) Suppose now a previous study at State Tech found 30% checked its web site on a regular basis. Use this result to estimate the sample size State U should use in its study to estimate the percent of its students that check the web site regularly at 95% confidence.