Convert incorrect data types: Correct the incorrect data types for ease of analysis. For example, if the numeric values are stored as strings, then it would not be possible to calculate metrics such as mean, median, etc. Some of the common data type corrections include string to number ('12,300' to '12300'), string to date ('2013-Aug' to '2013/08), number to string ('PIN Code 110001' to '110001), etc.