A measure of spread is a way of quantifying how spread out, or different, the points in a data set are. Some commonly used measures of spread are range, interquartile range, and standard deviation. Measures of spread are often used together with measures of center to give an idea both of what a typical value is and how much the data can be expected to deviate from it. Move the points around in the dot plot to generate new data. The applet identifies the range, interquartile range, mean absolute deviation, and standard deviation of the data set.