Median is the middle value of a group. It’s the number that would be right in the
middle of the list if you arranged the numbers from smallest to largest.
1, 4, 56, 59, 342, 697, 3455The median of that group is 59. If the number of values is even (which would
mean that there are two “middles”), then the median is the mean of these two
middle values.
3, 8, 45, 67, 107, 156, 223, 1302The median of that group is the mean of 67 and 107, or 87. (If you are given a
list of numbers that is not in numerical order, put it in order before looking for
the median.)
Mode is the value or values that appears the greatest number of times. The
mode of 3, 24, 95, 74, 74, 24, 56, 74, 61 is 74. The mode of 34, 46, 27, 1, 83, 46,
90, 63 is 46.
Standard Deviation
At least one problem on the SAT will include the term standard deviation. This
refers to the amount of dispersion among a set of data. For example, let’s say ten
test takers received the following scores:
800, 950, 1100, 1120, 1200, 1200, 1280, 1350, 1400, 1500Our mean, or average score, would be 1190. Let’s plot those scores on a graph.