The PAT Learner Guide mentions working with a data set other than the data set derived from the Questionnaire. From what I can tell it then does not award any marks for this extra work in the rubric. Based on the principle of “better safe than sorry” as well as an opportunity to find data that allows additional opportunities for the use of all the required Excel functions, I always make certain it is done.
In my post Phase 2 Excel analysis I discuss how to fulfil the requirements for “Level 4” analysis. Finding a data set specifically for this purpose makes a lot of sense.
For example: you could collect a data set from an American website containing data that needs to be converted from gallons to litres, and use the CONVERT function.