Statistics: Mean, Median & Standard Deviation

Central Tendency

Mean = Sum of values / Number of values

Median: middle value when sorted (average of two middle for even count)

Mode: most frequent value

Range = max - min

Standard deviation = measure of how spread out data is

- Larger SD = more spread out

- Adding a constant to all values: mean changes, SD stays same

- Multiplying all values by a constant: both mean and SD change

Median is resistant to outliers, mean is not

For weighted averages: multiply each value by its weight

You won't calculate SD on the SAT — just understand the concept

Statistics: Mean, Median & Standard Deviation | SAT Math Prep