Sir can you please explain the symbols that appear in the decision tree?
square box = It is a decision point where we have to decide whether to choose one or another alternative depend on a question’s wording
blob = It is a point where we have two ways (ie. two possible outcomes) of a decision taken at a decision point (ie. square box) provided in a question
These are the normal symbols, as I explain in my lectures on decision trees. However you obviously cannot be asked to draw one yourself in the exam, and so if the examiner provides one in the question then it will be made clear what symbols she is using.