# Measures of Central Tendency

The measures of central tendency are mean, median, and mode.

Mean
The mean takes all values in a set, adds them up, and divides by the sample size. This is what most people think of when they think of an "average".

Say you have relatives who sometimes help you with your website. When they do, they get paid a monthly sum for their help. You could figure out the mean of how much they work each week, across several months, and then calculate that out to give them a fair per-hour amount. You don't track specific hours every day, and the system is very flexible. By using a mean you account for heavy weeks and light ones.

Median
The median puts the numbers you have in order from smallest to largest. It then takes the number in the exact middle of that list, whatever it is.

When I talk with my low carb visitors about the carbs per day we take in, we usually go for a median value. Medians are less affected by outlying extreme values so if someone has a craving and eats something really bad, we still focus on the overall healthy trend. One minor craving shouldn't make a person feel awful about the entire day of progress.

Mode
The mode is the most frequently seen value in the list, wherever it falls in the sequence. I use this all the time when sorting out my inbox. There are certain people who bombard me with email on similar topics. If I sit down, order the list by item to see who is most frequent, and plow through that one set of messages, I can make substantial progress very quickly. Then I can work on the less frequent items.

Also when I run forum reports I look for the most frequently hit IDs. Those are the ones I can focus on and make the most impact with adding new content to them.

Statistics Basics