Take time to understand the section on standard deviation and variance. You will see these statistics in more advanced procedures. Although your instructor may require you to memorize the formulas, it is more important for you to understand how to interpret standard deviation and variance and when they can be appropriately used. Many hand calculators and all statistical software programs will calculate these measures of diversity for you, but they won’t tell you what they mean. Once you understand the meaning behind these measures, the formulas will be easier to remember.