13. The standard deviation is: A. The square root of the variance B. A measure of variability C. An approximate indicator of how numbers vary from the mean D. All of the above 14. Which of the following measures of central tendency could be computed on a variable that is measured on a nominal scale of measurement? A. Mean B. Median C. Mode D. All of the above 15. The nominal level of measurement is represented in which variable below? A. fear of crime B. temperature C. income D. gender 16. The ordinal level of measurement is represented in which variable below? A. fear of crime B. temperature C. income D. gender