When should one of mean, mode, and median be used over the other
In: 15
In addition to the distinctions that Ansuz07 made, I would offer that mean, median, and mode work with different levels of measurement. With *interval* and *ratio* levels of measurement (actual numbers, like an age or a dollar value), you can use all three. But sometimes that dataset is *ordinal*, meaning you can rank it but it doesn’t have specific numbers. Imagine that you’re describing the educational level of people in your neighborhood:
* 10% don’t have a high school diploma
* 45% have only a high school diploma
* 30% have a bachelor’s degree
* 10% have a master’s degree
* 5% have a doctorate degree
In this case, there’s no way to calculate a mean, but knowing the median is a high school diploma tells you something about the “average” education level of the area.
Sometimes data is *nominal,* meaning that you can’t even rank it, so the only measure of central tendency that you have is the mode.
Finally, I should note that (arithmetic) mean, median, and mode aren’t the only measures of central tendency. They’re just the most common. You have the weighted means, harmonic means, geometric means, trimeans, and lots of others. It gets even more complicated when the data is multi-dimensional, such as with coordinates. But I guess I’m getting far afield from your question.
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