Mean, median and mode are three types of questions that may be asked on the SAT and are great way to sort data for statistics and probability. The mean is the average of a set of numbers, the median is the middle of a sorted list of numbers and the mode is the most frequent number.
Mean
In order to find the mean of a set of numbers, we sum all the entries and then divide by the number of entries.
Find the mean of 25, 44, 67, 20, 19.
Step 1: Add up all of the entries.
25 + 44 + 67 + 20 + 19 = 175
Step 2: Divide by the number of entries.
There are 5 entries and so we divide 175 by 5. This gives us a mean of 35.
Median
In order to find the median of a set of numbers, we arrange of the entries from lowest to greatest and then find the middle number. If there are two middle numbers, the median is equal to the mean of the two numbers.
Find the mean of 25, 44, 67, 20, 19, 23.
Step 1: Arrange the numbers from lowest to greatest.
19, 20, 23, 25, 44, 67
Step 2: Eliminate entries one-by-one from each end until you have 1 or 2 entries left.
20, 23, 25, 44
23, 25
Step 3: If there is only one entry left, that is the median. Otherwise, take the mean of the remaining numbers.
The mean of 23 and 25 is 24.
Therefore the median is 24.
Mode
The mode is the number with the highest frequency in a set of numbers.
Find the mode of 25, 44, 25, 13, 44, 9, 44.
Step 1: Count the number of times each entry appears in the set.
9 appears once.
13 appears once.
25 appears twice.
44 appears 3 times.
Step 2: The mode is the number that has the greatest frequency.
The mode is 44.
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This article was written for you by Jeremie, one of the tutors with Test Prep Academy.