The Relative Standard Deviation (RSD) is also referred to as coefficient of variation (CV) in probability theory and statistics. RSD is a standardized measure of dispersion of a frequency distribution. Relative standard deviation is often expressed in terms of percentage. RSD is obtained by multiplying the standard deviation by 100 and dividing this product by the average. Below Relative Standard deviation formula can be used to find the COV %. The RSD formula is based on the mean and standard deviation of the data set.