I am trying to do a simple Naive Bayes classification, but I am getting a probability greater than zero. What am I doing wrong? I have included my calculations below.
Step 1: Prior. Calculate the prior probability of the class, i.e., the probability we would assign to the class before seeing any evidence. What percentage of all customers have churned? 0.48
Step 2: Evidence. Calculate the likelihood of the evidence: how common is the evidence among all examples? What percentage of all customers have a BS210 handset? 0.12
Step 3: Likelihood. Calculate the likelihood of seeing the evidence, given the class. What percentage of customers with a BS210 handset have churned? 0.916666667
Step 4: Posterior. Calculate the posterior probability of the class for a particular example. Given a new customer with BS210 handset, what is the likelihood that the customer will churn? Posterior = (Likelihood * Prior)/Evidence 3.666666667