According to the Pew Internet & American Life Project, many American adults spend significant amount of time on the Internet every day (Pew Internet Project, 2008). Google has a project that provides free wireless Internet in a medium-sized city. Among several factors that affect Googles decision, one factor is the percentage of adult smartphone users who are actively using social network apps. Google picked a random sample of 450 residents in one of the candidate cities, Rich-Addison, and collected the data in the Google sheet of Part A - Data Sets for Assessment Assignment.xlsx. Use this data set to answer questions 6 to 9.

6. [2 pt] Construct a 95% confidence interval for the true proportion of Rich-Addison residents who are actively using Facebook.

   95% confidence interval:

7. [2 pt] If everything else remains the same, what is the margin of error in a 98% confidence interval?

   Margin of error:

8. [3 pts] Google wants to know what percentage of users is actively using all three medias Facebook, Twitter, and an online chat/video tool (Skype, Facetime, etc.). What is 90% confidence interval for the true proportion of smartphone users who are actively using all three?

   90% confidence interval:

	Facebook	Twitter	O/C/V	All yes
Yes	226	159	273	0
No	223	291	177