Yue Bing is a new intern at Linkedin. She has designed a new recommendation algorithm for connecting Linkedin users to other users, and wants to see if it will cause an increase the average number of messages sent by Linkedin users. She will randomly sample one group of users from the Linkedin network and set up their accounts so that they use the new recommendation algorithm. She will then randomly sample another group of users, who will operate on the regular recommendation algorithm. She determines how many messages are sent by users over the course of year. She ends up assigning 19 users to the new algorithm, and 42 users to the old algorithm. She provides you with some of her data, though it is incomplete. New Old Sample Size 19 42 Sample Meani Standard Deviation 22 3.11 38.9 31.8 She insists all assumptions necessary for a confidence interval for a difference between two appropriate means have been verified. What distribution would we use to determine the critical value of a 95% confidence interval using her sample data? Select one: Oa. AT distribution with 60 degrees of freedom. Ob. AT distribution with 18 degrees of freedom. Oc. AT distribution with 41 degrees of freedom. Od. AT distribution with 42 degrees of freedom. e. A Z distribution of. AT distribution with 19 degrees of freedom. Yue Bing provides you the 95% confidence interval she computed for the difference between the the two parameters relevant to the problem (5.48, 8.72) messages per year. However, she doesn't know how to interpret what this means at all. Which statement below is a reasonable conclusion to draw from this confidence interval, at a 95% confidence level? Select one: a. On average, Linkedin users would send between 5.48 and 8.72 messages per year total with the new algorithm. b. There's not enough information to suggest that on average, all Linkedin users would differ in the number of messages sent with the new algorithm than with the old algorithm. c. On average, all Linkedin users would send more messages with the new algorithm than with the old algorithm. d. On average, all Linkedin users would send fewer messages with the new algorithm than with the old algorithm.