C) For a sample 1000 Twitter users, Tele-Market Research reports an average age of 39. If the population standard deviation is 9.5 years, what would be the upper bound for a 90% confidence interval estimate of the mean age of all Twitter users?

a. 35.2

b. 39.5

c. 33.4

d. 41.2

e. 46.1

D) In a random sample of 341 U.S. companies, the average number of paid sick days allowed company employees was 18.65. The margin of error was reported as 1 day, at the 95% confidence level. Show the upper bound for the 95% confidence 10 interval estimate of the average number of paid sick days allowed employees by the population of all U.S. companies.

a. 18.76

b. 20.34

c. 19.65

d. 18.08

e. 19.13