Ans. C: Dispersion of values about the mean The steps are: Compute the mean for the data set. Compute the detion by subtracting the mean from each value. Square each individual detion. Add up the squared detions. Divide by one less than the sample size. Take the square root. Standard detion gives us an idea of the spread of the dispersion; that the larger the standard detion, the greater the dispersion of values about the mean.