# Lesson 3: Central Tendency

- Mode - most common value
- Median - value in the middle
- Mean - average
- Uniform distribution
- Flat line
- No mode / multiple modes

```
x-bar = sum(x) / n
mu = sum(x) / N
```

- Properties of mean
- All scores in distribution affect mean
- Mean can be described with a formula
- Many samples from pop have similar mean
- Mean of a sample can be used to make inferences about it
- Extreme values can drastically alter mean

- Properties of median
- Robust - not affected by outliers

- Normally distributed data generally has a similar mode, median and mean