Data-Driven Digital Marketing
MKTG 367: Data-Driven Digital Marketing
A6 Confidence Intervals
1. In the past month, your website has had 566 visitors and a bounce rate of 47.7%.
a. [5 pts] What is the confidence interval for the bounce rate?
b. [3pts] What does this mean?
2. You are conducting an A/B test comparing two different versions of a newsletter for a charity with 500 potential donors in each group. The A email has an open rate of 31.1% and a click rate of 16.1%. The B email has an open rate of 31.5% and 20.2%.
a. [4 pts] What is the confidence interval for the difference in open rate?
b. [1 pts] Is this difference significant?
c. [4 pts] What is the confidence interval for the difference in click rate?
d. [1 pts] Is this difference significant?
e. [4 pts] If you were reporting the results of this test to others at the charity, what would you write in the email? Keep it as short and clear as possible.
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. [5 pt] What is the confidence interval for the difference in average session length?
b. [2 pt] Is this a statistically significant difference?
c. [1 pt] Should you tell your boss?
d. [bonus 1 pt] What would you do next?
