Mode: most frequently occurring observation o o. Can be used with variables at all three levels of measurement: most often used with nominal level variables o. Count the number of times each score occurs. The score that occurs most often is the mode. If the variable is presented in a frequency distribution, the mode is the largest category. If the variable is presented in a line chart, the mode is the highest peak. Median: observation that divides the distribution in half, after ranking all observations from lowest through to highest (and vise versa) o. The observation that is at the exact center if distribution: ordinal, interval or ratio level data, most stable o o o. Can be used with variables measured at the ordinal or interval-ratio level variables. Can not be used for nominal level measurements o. If n is odd: the median is the score of the middle case.