Standard Deviation and Data Representation
This page expands on standard deviation and introduces data visualization techniques.
The formula for standard deviation is provided: s = √(Σ(x - x̄)² / n)
Definition: Standard deviation measures the average distance of data points from the mean.
Stem and leaf diagrams are introduced as a way to sort and display data.
Box plots (box and whisker diagrams) are explained, showing how they represent the five-number summary of a dataset.
Highlight: Box plots are useful for comparing distributions and identifying outliers in A Level Statistics.
The page also covers finding quartiles from frequency tables and introduces the concept of skewness in data distributions.
Example: Outliers are defined as data points below Q1 - 1.5(IQR) or above Q3 + 1.5(IQR).