Which of the following is used to compare two data sets taken on two different scales of measurement?

Ans. b. Coefficient of variation (Ref: http://en.wikipedia.org/wiki/Coefficient_of_yariation)Coefficient of variation is used to compare two data sets taken on two different scales of measurement.'For comparison between data sets with different units or widely different means, one should use the coefficient of variation instead of the standard deviation. - http://en.wikipedia.org/wiki/Coefficient_of_variationCoefficient of variation (CV)Coefficient of variation (CV) is a normalized measure of dispersion of a probability distribution or frequency distribution.It is defined as the ratio of the standard deviation to the mean.The absolute value of the CV is sometimes known as relative standard deviation (RSD). which is expressed as a percentage.AdvantagesDisadvantages* The coefficient of variation is useful because the standard deviation of data must always be understood in the context of the mean of the data.* In contrast, the actual value of the CV is independent of the unit in which the measurement has been taken, so it is a dimensionless number.* For comparison between data sets with different units or widely different means, one should use the coefficient of variation instead of the standard deviationQ.* When the mean value is close to zero, the coefficient of variation will approach infinity and is therefore sensitive to small changes in the mean. This is often the case if the values do not originate from a ratio scale.* Unlike the standard deviation, it cannot be used directly to construct confidence intervals for the mean.