In: Statistics and Probability
3. (No computer output is accepted) A typical person in America has 155 friends in Facebook, 210 followers in Instagram and 155 followers in Twitter according to USA Tomorrow. A random sample of 30 people is selected and the following summary statistic are obtained. (Assume that the variables are normally distributed.)
Sample Mean for Facebook is 120.7
Sample Mean for İnstagram is 210.3.
Sample Mean for Twitter is 154.5
Sample Standard Deviation for Facebook is 5.2
Sample Standard Deviation for İnstagram is 7.85
Sample Standard Deviation for Twitter is 19
a) Construct a 99% two-sided confidence interval for the mean number of friends in Facebook for all people in America.
b) Construct a 99% two-sided confidence interval for mean number of followers in Instagram for all people in America.
c) Construct a 99% two-sided confidence interval for the mean number of followers in Twitter for all people in America.
d) Does this sample support the claim of USA Tomorrow? Explain your answer.
(Use 4 significant digits in your results. For example, if your
answer is 20/7, write 2.8571. Moreover, do not leave the solution
as 20/7. and show your answers in detail)