Welcome to Really Simple Statistics (RSS). There are lots of places online where you can ponder over the minute details of complicated equations but very few places that make statistics understandable to everyone. I won’t explain exceptions to the rule or special cases here. Let’s just get comfortable with the fundamentals
What is a mean?
Well, it’s certainly not this angry little guy!
idahoeditor from morguefile
There are a few kinds of means that smartie pants like to mention, but most people really are referring to the “average.” Averages are often the easiest way to describe a group using one single number.
For example, the average of
1 1 5 6 7
What is a median?
The median is the middle number in an ordered list. In other words, half of the numbers are larger and half of the numbers are smaller.
The mean and median often work well together to describe data. If you think about incomes, the average US household income might actually be $500 000 because there is a small group of people who make ridiculously huge salaries (think professional athletes, music and film celebrities, executives of private corporations). But, that average number doesn’t really reflect the salaries that the ‘average’ family earns. So, then we might look at the median US household income which could be $50 000 dollars. Half of people make more than that, and half of people make less than that. Now THAT number makes more sense.
For example, with the same set of numbers…
1 1 5 6 7 … The median is 5
1 6 1 7 5 … The median is still 5
5 1 7 6 1 … And the median is still 5
What is the mode?
Again, people follow me here! I’m not talking about ice cream as in pie ‘a la mode’, though I could really go for some right now!
The mode is the most common number in a list. The mode is useful if you want to say things like “Most people each three meals a day” or “Most people use one bar of soap every week.” Using the same list as above, the mode in this list…
1 1 5 6 7 …. is 1.
Really Simple Statistics!