Suppose I have a customer satisfaction survey with around 20 questions, asking customer's opinions on Company X.
For each question and each company, the customer rates the company on a 1-5 scale, so my data looks something like:
Q1 Q2 Q3 ... Q20 Customer 1 4 4 3 ... 2 Customer 2 4 4 3 ... 2 ... Customer 10000 2 1 3 ... 5
I would then like to cluster customers based on their answers (the patterns of their answers).
What type of clustering would be appropriate in this case? I don't know the number of clusters I am looking for.
What if each customer rated more than one company? (so they completed more than one survey)