In America the prices of medical procedures can vary greatly, so savvy Americans tend to shop around for a good deal. In this challenge you will take the role of a data journalist trying to investigate price differences among medical procedures. More specifically, you want to find the top 5 procedures that show the largest variety in terms of pricing from hospital to hospital (in statistics, you would call this high standard deviation). The data you have at hand for this investigation is not uniform and requires inspection in order to be properly read and processed. For simplicity, compare all average charges for the 25 most common outpatient procedures performed by hospitals from the Kaiser Foundation Hospitals and Sutter Hospitals only. For Kaiser Foundation, the relevant data is in Excel files with "...Common25..." in their names; for Sutter, the relevant Excel files contain "...CDM_All..." in their names. Beware of hidden sheets.