1.The Pew Internet and American Life Project reported findings from a study in 2003 that 18 percent of Internet users have used it to search for information regarding experimental treatments or medicines. The sample consisted of 1220 adult Internet users, and information was collected from telephone interviews. We wish to construct a 95 percent confidence interval for the proportion of Internet users in the sampled population who have searched for information on experimental treatments or medicines.

2.A research group would like to conduct a mental health study in a small town to determine the mean number of people who have had mental health issues in their life.The error in estimating the mean is to be less than 8% with a 98% level of confidence.No estimate of the population proportion exists.What is the size of the sample needed for this study?

3.A study is undertaken to test the emission levels of minivans. At the outset, a research hypothesis is established that states more than 75% of minivans meet emission standards (Null hypothesis is that 75% meet the standard). An alpha value of 0.05 is chosen. A sample of 180 minivans is then selected.Of these cars, 130 cars met the standard. What conclusion can be reached about the null hypothesis?