3.1: Introduction to Measures of Central Tendency
- Page ID
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We’ve seen that we can get a sense of data by plotting frequency data on a graph. These frequency charts show us what the whole distribution of scores looks like, approximately how big and small the scores are, and how similar and different the scores are from another. In addition to summarizing distributions of scores with graphs, we can summarize a whole set of scores using just a few numbers.
From many numbers to one
Measures of central have one important summary goal: to reduce a pile of numbers to a single number (or a few) that can be used to describe that distribution of scores. We already know that looking at lots of numbers is hopeless. If your boss ever asks the frightening question, “hey, what are all these numbers like?”. You can find a number that represents the center of the distribution of scores to answer your boss's questions. Each of the following sections will look at a different way to define the center of a distribution: the mode, the median, and then the mean. Each of these are most useful in different situations, but they can be used together to predict what the frequency distribution could be shaped like (if you couldn't see a frequency line graph or histogram).
But before we get into learning about these measures of central tendency, let's first go back to our earlier math classes to remember what the symbols mean and other mathematical operations.