Google picked a random sample of 425 residents in one of the candidate cities, Rich-Addison, and collected the data in the "Google" sheet of "Part A, excel. Use this data set to answer questions 6 to 9.

Facebook Yes:211

Facebook No:214

Twitter Yes:124

Twitter No:301

Online Chat/Video Yes:265

Online Chate/Video No:160

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

95% confidence interval:

If everything else remains the same, what is the margin of error in a 99% confidence interval?

Margin of error:

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:

Google wants to know if there is strong evidence that more than 25% of smartphone users actively use Twitter. Use the sample data to perform the hypothesis test at the 1% significance level. For full credits, you need to specify the null and alternative hypotheses, appropriate test- statistic value, p- value and conclusion.

Parameter to be tested:

0:

:

Test-statistics:

p-value:

Conclusion: