Final answer:
The Coefficient of variation is used to provide a relative value of risk when comparing distributions with unequal means, as it standardizes the level of volatility or dispersion relative to the mean of the distributions.
Step-by-step explanation:
The item that can be used to give us a relative value of risk when the means of the distributions are not equal is c) Coefficient of variation. The coefficient of variation (CV) is a statistical measure of the dispersion of data points in a data series around the mean. It is calculated as the ratio of the standard deviation to the mean. This measure is particularly useful in comparing the degree of variation from one data series to another, even if the means are drastically different from one another. The CV is expressed as a percentage which makes it a dimensionless number, allowing for direct comparisons.
For example, if we have two different investments, with different means and standard deviations, we can use the coefficient of variation to assess which investment has more risk relative to its expected return. The investment with the higher CV would be considered riskier compared to one with a lower CV, as it has a greater level of dispersion or variability in its returns.