Suppose we wanted to answer the following question: Does one's income differ according to their belief in ghosts? This is something we can use the Cards Against Humanity Pulse of the Nation poll to try to answer. For your convenience, we have made a subset of the data available to you in a CSV file called 201709-CAH_PulseOfTheNation.csv. a) What is the mean Income for people who believe in ghosts? For people who don't believe in ghosts