Question: Internet telephone calls You can use Voice over Internet Protocol (VoIP) to make long-distance calls over the Internet. One of the most popular VoIP services is Skype. How will the appearance of ads during calls affect the use of this service? Researchers design an experiment to find out. They recruit 300 people who have not used Skype before to participate. Some people get the current version of Skype with no ads. Others see ads whenever they make calls. The researchers are interested in frequency and length of phone calls.