Why spread matters
Why spread matters

A measure of location, such as the mean, tells you where the data is centred. A measure of spread tells you how tightly the values cluster around that centre.
Step-by-step lessons on Edexcel AS Level Maths 2.4 Variance and Standard Deviation. Each one builds up to exam-style questions. Build fluency in the core algebra, surds and trigonometry topics early, since they underpin the calculus, statistics and mechanics content that follows.