UPSC NDA I 2015 Mathematics Solved Paper

Any one of the measures of central tendency can be used to construct index numbers. However, median and mode are not generally used since they do not yield accurate results. Arithmetic and Geometric means are usually used for averaging the relatives. Out of the above two, G.M gives more accurate results and is therefore preferred over A.M.
Hence the correct answer to the above question is ‘Geometric Mean’.