A survey of 305 adults found that during the last year, 75 traveled by plane but not by train, 75 traveled by train but not by plane, 20 traveled by bus but not by plane or by train, 60 traveled by bus and plane, 35 traveled by all three, and 235 traveled by plane or train. How many did not travel by any of these modes of transportation?

Definition Definition Measure of central tendency that is the value that occurs most frequently in a data set. A data set may have more than one mode if multiple categories repeat an equal number of times. For example, in a data set with five item—3, 5, 5, 29, 473—the mode is 5 because it occurs twice and no other value occurs more than once. On a histogram or bar chart, the element with the highest bar represents the mode. Therefore, the mode is sometimes considered the most popular option. The mode is useful for nominal or categorical data (e.g., the most common color car that users purchase), but it is problematic for continuous data because it is more likely not to have any value that is more frequent than the other.