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. [4 pt] What is the confidence interval for the difference in average session length?

b. [1 pt] Is this a statistically significant difference?

c. [1 pt] Should you tell your boss?

d. [1 pt] What would you do next?