3. You are testing two different landing pages for a retail website. You test the pages with 100 visitors in each group and the first landing page results in an average session length of 2.5 min (sd = 3.7 min) and the second produces an average session length of 3.5 min (sd = 4.4 min). A one-minute increase in session length seems like a lot and you need to decide whether to report this to your boss, who is the head of digital marketing.

a. What is the confidence interval for the difference in average session length?

b. Is this a statistically significant difference?

c. Should you tell your boss?

d. What would you do next?